Anatomy and Physiology 1

RELATIONSHIP BETWEEN ANATOMY AND PHYSIOLOGY ANATOMY - the study of the structure and shape of the body and body parts & their relationships to one another. - the term anatomy comes from the Greek words meaning to cut (tomy) apart (ana) - is the study of the structure and the relationships among structures. - the art of separating the parts of an organism in order to ascertain their position, relations, & structure - cutting something up to see what’s inside (structure) - study of anatomy helps in understanding the functions of body. PHYSIOLOGY - the study of how the body and its parts work or function - physio =nature ology = the study of - it has many subdivisions. For example, neurophysiology explains the working of the nervous system , and cardiac physiology studies the function of the heart. - is the study of the normal function of the human body (to maintain life) - Human physiology is the scientific study of the chemistry and physics of the structures of the body and the ways in which they work together to support the functions of life. - much of the study of physiology centers on the body’s tendency toward homeostasis. - Anatomy and Physiology are always related Structure determines what functions can take place. For example, the lungs are not muscular chambers like the heart and can not pump blood, but because the walls of lungs are very thin, they can exchange gasses and provide oxygen to the body. DIVISIONS OF ANATOMY 1. - GROSS ANATOMY Structures that can be seen with the eye Muscles, bones, various organs A type of anatomy that can be undertaken without a microscope - considers large structures such as the brain 2. SURFACE ANATOMY (EXTERNAL) - anatomy that we can see at the surface of the body 3. REGIONAL ANATOMY (SPECIFIC AREA) - complete anatomy (internal) of a specific region of the body (learning every blood vessel, muscle, bones, etc. in the arm) in medical school - is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen. - Studying regional anatomy helps us appreciate the interrelationships of body structures, such as how muscles, nerves, blood vessels, and other structures work together to serve a particular body region. 4. SYSTEMIC ANATOMY (ORGAN SYSTEMS) - the body is divided into 11 organ systems - is the study of the structures that make up a discrete body system—that is, a group of - structures that work together to perform a unique body function. For example, a systemic anatomical study of the muscular system would consider all of the skeletal muscles of the body. Study of specific system: *Integumentary *Endocrine *Cardiovascular *Reproductive *Nervous *Skeletal *Muscular *Immune *Respiratory *Digestive *Urinary *Lymphatic 5. - MICROSCOPIC ANATOMY Structures that cannot be seen with the eye Need to use a microscope Cytology = study of cells Histology = study of tissues Requires the use of a microscope (e.g. light or phase microscope) - Microscopic anatomy can deal with the same structures, though at a different scale. CHARACTERISTICS OF LIFE 1. - ORGANIZATION organize structure follows hierarchy living things are made of cells, which is the basic unit of life. If something is going to be alive, it should be made of cells 2. RESPONSIVENESS - is the ability of an organism to adjust to changes in its internal and external environments. - ability to sense and react to a certain stimulus and changes from both internal and external - Example: Changes in an organism’s internal environment, such as increased body temperature, can cause the responses of sweating and the dilation of blood vessels in the skin in order to decrease body temperature. 3. MOVEMENT - a type of response to stimuli - Human movement includes not only actions at the joints of the body, but also the motion of individual organs and even individual cells. - ability of a organism in displacement, move from one location to another 4. DEVELOPMENT AND GROWTH - Development is specialized in structure and function to perform certain tasks in the body - Development is all of the changes the body goes through in life includes the process of differentiation, in which unspecialized cells become specialized in structure and function to perform certain tasks in the body - Development also includes the processes of growth and repair, both of which involve cell differentiation. - knowledge, IQ and EQ - - Growth is the increase in body size. Humans, like all multicellular organisms, grow by increasing the number of existing cells, increasing the amount of non-cellular material around cells (such as mineral deposits in bone), and, within very narrow limits, increasing the size of existing cells. cell division specifically “Mitosis” is responsible for growth - Mitosis = divides in result to be alike Meiosis = sex cells; haploid Gametes = produce through meiosis 5. REPRODUCTION - is the formation of a new organism from parent organisms. In humans, reproduction is carried out by the male and female reproductive systems. Because death will come to all complex organisms, without reproduction, the line of organisms would end. - - Sexual = copulation; with the use of sex organs - 2 parents supply DNA - male and female reproductive system - Anabolism- process where simple molecules are gathered to create complex molecules - storing/building of energy - smaller to larger - To study the chemical level of organization, scientists consider the simplest building blocks of matter: subatomic particles, atoms and molecules - Elements = all matter in the universe is composed of one or more unique pure substances - ex: hydrogen, oxygen, carbon, nitrogen, calcium, and iron - Atom = the smallest unit of any of elements - are made up of subatomic particles such as the proton, electron and neutron - Molecule = formed by two or more atoms combined ex: water molecules, proteins, and sugars found in living things - the chemical building blocks of all body structures - Cell = the smallest independently functioning unit of a living organism - each bacterium is a single cell - all living structures of human anatomy contain cells, and almost all functions of human physiology are performed in cells or are initiated by cells - perform all functions of life - it is the basic functional and structural unit of body Catabolism- process where complex molecules were broken down of energy - breaking down of energy - larger to smaller 7. GENES - traits you have inherited to your parents/ ancestor - hereditary/traits - genetics - dominant and recessive 8. HOMEOSTASIS - balance between fluids/ chemical components within the body - is the state of steady internal conditions maintained by living things. Passive Transport = without energy Active Transport = using energy Osmosis = segregate Phagocytosis = Cell eating Endocytosis = Cell drinking THE LEVELS OF ORGANIZATION Asexual = absence of sexual act - pollination, cross pollination 6. METABOLISM - ability of organism to utilize energy - ex: living things take in energy for maintenance and growth - - - Organelles = a variety of tiny functioning units together with water-based cellular fluid - Tissue = is a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function - Organ = is an anatomically distinct structure of the body composed of two or more tissue types - each organ performs one or more specific physiological functions - Organ system = is a group of organs that work together to perform major functions or meet physiological needs of the body. - Organism = a individual living being - consists of different systems REFERENCES: https://www.cuyamaca.edu/people/greg-brulte/ files/test-1/A-intro.pdf https://www.academia.edu/33633526/Chapter_ 1_Introduction_to_Human_Anatomy_physiology NOTE: Some information were gathered online and others were from PDFs downloaded years ago Dorsal Proximal Distal ANATOMICAL POSITION - in the anatomical position, the body is standing erect and facing forward, the feet are together, and the arms are hanging at the sides with the palms facing forward Medial Lateral Superficial Deep Back/ Toward the back Nearest/ Closer to a point of attachment Distant/ Farther from a point of attachment Toward the midline Away from the midline Toward to the surface of the body Toward the interior of the body BODY PARTS AND REGIONS - used to designate specific areas within The major body divisions CENTAL REGION OF THE BODY (AXIAL PARTS) 1. Head 2. Neck 3. Trunk- can be divided into: a) Throrax (Chest) b) Abdomen (region between thorax and pelvis) c) Pelvis (inferior end of the trunk associated with the hips) DIRECTIONAL TERMS - describe parts of the body relative to each other Supine Prone Superior Inferior Anterior TERM Posterior Ventral DEFINITION Lying face upward Lying face downward Higher/ above Lower/ below Front/ Toward the front of the body Back/ toward the back of the body Belly/ Toward the belly UPPER LIMB (APPENDICULAR PARTS) 1. Arm- extends from the shoulder to the elbow 2. Forearm- extends from the elbow to wrist 3. Wrist 4. Hand LOWER LIMB (APPENDICULAR PARTS) 1. Thigh- extends from the hip to the knee 2. Leg- extends from the knee to the ankle 3. Ankle 4. Foot ABDOMEN (APPENDICULAR PARTS) - often subdivided superficially into four sections or quadrants by to imaginary lines that intersect at the navel a. Quadrants- right-upper (RUQ), left-upper (LUQ), right-lower (RLQ), and left-lower (LLQ) b. Regions- uses four imaginary lines that created an imaginary tic-tac-toe figure on the abdomen, resulting nine regions: 1. Epigastric- located superior to the umbilical region 2. Right hypochondriac- lie lateral to the epigastric region and deep to the ribs (chondro = cartilage) 3. Left hypochondriac- lie lateral to the epigastric region and deep to the ribs (chondro = cartilage) 4. Umbilical- the centermost region deep to and surrounding the umbilicus (navel) 5. Right lumbar- lie lateral to the umbilical region (lumbus = loin) 6. Left lumbar- lie lateral to the umbilical region (lumbus = loin) 7. Hypogastric- located inferior to the umbilical region 8. Right iliac- located lateral to the hypogastric region (iliac = superior part of the hip bone) 9. Left iliac- located lateral to the hypogastric region (iliac = superior part of the hip bone) PLANES - imaginary flat surface - the body is often cut, or sectioned, along a flat surface TERMS Sagittal Plane Runs vertically through the body and separates it into right and left parts Median Plane A sagittal plane that passes though the midline of the body, dividing it into equal right and left halves Transverse/ Horizontal Runs parallel to the Plane surface of the ground, dividing the body into superior and inferior parts Frontal/ Coronal Plane Runs vertically from right to left and divides the body into anterior and posterior parts Longitudinal Section A cut through the long axis of the organ Transverse Section/ A cut at a right angle to Cross Section the long axis Oblique Section A cut is made across the long axis at other than a right angle - BODY CAVITIES - these cavities are closed to the outside and provide different degrees of protection to the organs contained within them. 1. NASAL CAVITY - Open to the outside of the body - located within and posterior to the nose, the nasal cavity is part of the respiratory system passageways 2. DORSAL BODY CAVITY - which protects the fragile nervous system organs, has two subdivisions a. CRANIAL CAVITY - in the skull, encases the brain b. VERTEBRAL OR SPINAL CAVITY - runs within the bony vertebral column, encloses the delicate spinal cord. The spinal cord is essentially a continuation of the brain, and the cranial and spinal cavities are continuous with one another. 3. VENTRAL BODY CAVITY - the more anterior and larger of the closed body cavities - has two major subdivisions: a. THORACIC CAVITY - superior subdivision,is surrounded by the ribs and muscles of the chest - It is further subdivided into lateral pleural cavities each enveloping a lung, and the medial mediastinum. The mediastinum contains the pericardial cavity, which encloses the heart, and it also surrounds the remaining thoracic organs (esophagus, trachea, and others). - The thoracic cavity is separated from the more inferior abdominopelvic cavity by the diaphragm, a dome-shaped muscle important in breathing. b. ABDOMINOPELVIC CAVITY - has two parts. - these regions are not physically separated by a muscular or membrane wall - the abdominal and pelvic cavities are not aligned with each other. Instead, the bowl-shaped pelvis tips away from the perpendicular the ventral body cavity houses internal organs collectively called the viscera or visceral organs. 4. ABDOMINAL CAVITY - is bounded primarily by the abdominal muscles and contains the stomach, the intestines, the liver, the spleen, the pancreas, and the kidneys. 5. PELVIC CAVITY - is a small space enclosed by the bones of the pelvis and contains the urinary bladder, part of the large intestine, and the internal reproductive organs. 6. ORAL AND DIGESTIVE CAVITIES - commonly called the mouth, contains the teeth and tongue - it is part of and continuous with the cavity of the digestive organs, which opens to the body exterior at the anus. 7. ORBITAL CAVITIES - (orbits) in the skull house the eyes and present them in an anterior position. 8. MIDDLE EAR CAVITIES - the middle ear cavities in the skull lie just medial to the eardrums. These cavities contain tiny bones that transmit sound vibrations to the hearing receptors in the inner ears 9. SYNOVIAL CAVITIES - are joint cavities - they are enclosed within fibrous capsules that surround freely movable joints of the body - like the serous membranes, membranes lining synovial cavities secrete a lubricating fluid that reduces friction as the bones move across one another. SEROUS MEMBRANES - line the trunk cavities and cover the organs of these cavities - to understand the relationship between serous membranes and an organ, imagine pushing your fist into an inflated balloon. The inner balloon wall in contact with your fist (organ) represents the visceral serous membrane, and the outer part of the balloon wall represents the parietal serous membrane - the part of the membrane lining the cavity walls is called the parietal serosa . It folds in on itself to form the visceral serosa, covering the organs in the cavity. - The cavity, or space, between the visceral and parietal serous membranes is normally filled with a thin, lubricating film of serous fluid produced by the membranes - As an organ rubs against another organ or against the body wall, the serous fluid and smooth serous membranes reduce friction. Thoracic cavity contains three serous membrane-lined cavities: 1. PERICARDIAL CAVITY - surrounds the heart . The visceral pericardium covers the heart, which is contained within a connective tissue sac lined with the parietal pericardium. The pericardial cavity, which contains pericardial fluid, is located between the visceral pericardium and the parietal pericardium 2. TWO PLEURAL CAVITIES - surrounds each lung, which is covered by visceral pleura. Parietal pleura lines the inner surface of the thoracic wall, the lateral surfaces of the mediastinum, and the superior surface of the diaphragm. The pleural cavity is located between the visceral pleura and the parietal pleura and contains pleural fluid. - - Abdominopelvic cavity contains a serous membrane-lined cavity called the peritoneal cavity. Visceral peritoneum covers many of the organs of the abdominopelvic cavity. Parietal peritoneum lines the wall of the abdominopelvic cavity and the inferior surface of the diaphragm. Peritoneal cavity is located between the visceral peritoneum and the parietal peritoneum and contains peritoneal fluid. Serous membranes can become inflamed—usually as a result of an infection. Pericarditis is inflammation of the pericardium Pleurisy is inflammation of the pleura - Peritonitis is inflammation of the peritoneum. POSTERIOR BODY LANDMARKS Abdominal Anterior body trunk inferior to ribs Acromial Point of shoulder Antebrachial Forearm Antecubital Anterior surface of elbow Axillary Armpit Brachial Arm Buccal Cheek area Carpal Wrist Cervical Neck region Coxal Hip Crucal Anterior leg; shin Deltoid Curve of shoulder formed by large deltoid muscle Digital Fingers, toes Femoral Thigh (applies to both anterior and posterior) Fibular Lateral part of leg Frontal Forehead Inguinal Area where thigh meets body trunk; groin Mental Chin Nasal Nose area Oral Mouth Orbital Eye area Patellar Anterior knee Pectoral Relating to, or occurring in or on, the chest Pelvic Area overlying the pelvis anteriorly Pubic Genital region Sternal Breastbone area Tarsal Ankle region Thoracic Are between the neck and abdomen, supported by the ribs, sternum and costal cartilages; chest Umbilical Navel POSTERIOR BODY LANDMARKS Calcaneal Heel or foot Cephalic Head Femoral Thigh Gluteal Buttock Lumbar Area of back between ribs and hips, loin Occipital Posterior surface of head or base of skull Olacranal Posterior surface of elbow Popliteal Posterior knee area Sacral Area between hips at base of spine Scapular Shoulder blade region Sural Posterior surface of leg; calf Vertebral Area of spinal column REFERENCE: Essentials of Anatomy and Physiology 5th Edition. Scanlon, V.C. & Sanders, T., 2007. F.A. Davis Company, Philadelphia. (PDF) Essentials of Human Anatomy & Physiology 12th Edition. Marieb, E.N & Keller, 2016. S.M. Boston : Pearson. (PDF) Seeley’s Essentials of Anatomy & Physiology, Ninth Edition. VanPutte, C., Regan, J., Russo, A., 2016. McGraw-Hill Education, 2 Penn Plaza, New York, NY. (PDF) e. 6 carbons= Hexoses CHEMICAL COMPONENTS OF THE CELL - can be divided into two major groups: Organic and Inorganic compounds A. ORGANIC COMPOUNDS - are chemical compounds that contain the element carbon -Organic compounds in the cell include carbohydrates, protein, lipids and nuclei acids. Some of these compounds are synthesised by the cell itself. - are carbon containing compounds, and make up about 95% of the dry weight of the protoplasm THE IMPORTANCE OF ORGANIC COMPOUNDS IN THE CELL: A. CARBOHYDRATES - components carbon “carbo” and components of water “hydrate” - Supply energy for cell processes - A means of storing energy - Give structural support to cell walls - classfified into 4 subtypes: 1. MONOSACCHARIDES - mono= “one”; saccar= “sweet” - simple sugars, most common of which is Glucose - number of carbons usually ranges from 3-7 - most monosacc ends with the suffix -ose - If sugar has: a. Aldehyde group= known as Aldose b. Ketone group= Ketose c. 3 carbons= Trioses d. 5 carbons= Pentoses  GLUCOSE (C6H1206) (ENERGY) - important source of energy for humans - during cellular respiration, energy is released from here and that energy is used to help make ATP (adenosine triphosphate) - plants synthesize Glucose using CO2 and water and Glucose is used for energy requirements for the plant - excess glucose is often stored as starch that is catabolized by humans and other animals that feed on plants - Aldose  GALACTOSE (MILK SUGAR) - part of lactose - Aldose  FRUCTOSE (FRUITS) - found in sucrose - Ketose 2. DISACCHARIDES - di= “two” - form when two monosaccharides undergo a dehydration reaction - Dehydration Reaction- to put together while losing water -monomers combine with each other using covalent bonds to form larger molecules known as Polymers and so monomers release water molecules as byproducts - Hydrolysis- Polymers are broken down into monomers -a reaction in which a water molecule is used during breakdown  LACTOSE (MILK) - disaccharide consists of monomers Glucose and Galactose  MALTOSE (MALT SUGAR) - formed by a dehydration reaction between two glucose molecules  SUCROSE (TABLE SUGAR) - composed of monomers Glucose and Fructose 3. POLYSACCHARIDES - poly= “many” - a long chain of monossacharides linked by glycosidic bonds  STARCH (WATER) - stored from of sugars in plants - made up of a mixture of amylose and amylopectine - plants are able to synthesize glucose - excess glucose is stored in different plant parts - starch in seeds provide foods for the embryo - starch consumed by humans are broken down by enzymes into smaller molecules such as maltose and glucose -made up of glucose monomores B. LIPIDS - from the Greek word lipos, meaning "fat" - are naturally occurring, nonpolar substances that are mostly insoluble in water (with the exceptions being the short-chain volatile fatty acids and ketone bodies), yet soluble in nonpolar solvents (like chloroform and ether) - Store large amounts of energy over long periods of time - Act as an energy source - Play a major role in the structure of the cell membranes - Act as a source of metabolic water - Reduce the loss of water by evaporation - They serve as membrane components (cholesterol, glycolipids and phospholipids), storage forms of energy (triglycerides), precursors to other important biomolecules (fatty acids), insulation barriers (neutral fat stores), protective coatings to prevent infection and excessive gain or loss of water, and some vitamins (A, D, E, and K) and hormones (steroid hormones) - major classes: 1. Saturated and unsaturated fatty acids (short, medium, and long-chain)  GLYCOGEN (HUMAN) - storage form of glucose in humans and other vertebrates - made up of monomers of glucose - animal equivalent of starch and is highly branched molecule usually stored in liver and muscle cells - whenever blood glucose levels decrease, glycogen is broken down to release glucose with process glycogenolysis  CELLULOSE - most abundant natural biopolymer - cell wall of plants is mostly made up of cellulose; provides structural support to the cell 2. Triglycerides, lipoproteins {i.e., chylomicrons (CMs) 3. Very low density (VLDL),low density (LDL), intermediate density (IDL), and high density lipoproteins (HDL)} 4. Phospholipids and glycolipids, steroids (cholesterol, progesterone, etc.), and eicosanoids (prostaglandins, thromboxanes, and leukotrienes) - All lipids can be synthesized from acetyl-CoA, which in turn can be generated from numerous different sources, including - - carbohydrates, amino acids, short-chain volatile fatty acids (e.g., acetate), ketone bodies, and fatty acids. Simple lipids include only those that are esters of fatty acids and an alcohol (e.g., mono-, di- and triglycerides) Compound lipids include various materials that contain other substances in addition to an alcohol and fatty acid (e.g., phosphoacylglycerols, sphingomyelins, and cerebrosides) derived lipids include those that cannot be neatly classified into either of the above (e.g., steroids, eicosanoids, and the fat-soluble vitamins) C. PROTEINS - Act as building blocks of many structural components of the cell ; required for growth - Form enzymes which catalyse chemical reactions - Form hormones which control growth and metabolism - are amino acid polymers responsible for implementing instructions contained within the genetic code - Twenty different amino acids are used to synthesize proteins, about half are formed as metabolic intermediates, while the remainder must be provided through the diet. - Each protein formed in the body, unique in its own structure and function, participates in processes that characterize the individuality of cells, tissues, organs, and organ systems - A typical cell contains thousands of different proteins, each with a different function, and many serve as enzymes that catalyze (or speed) reactions - Other proteins transport different compounds either outside or inside cells; ex:  lipoproteins and transferrin (an iron-binding protein) in plasma -  bilirubinbinding proteins in liver cells some act as storage proteins; ex:  myoglobin binds and stores O2 in muscle cells) others as defense proteins in blood or on the surface of cells; ex: clotting proteins and immunoglobulins others as contractile proteins; ex:  the actin, myosin and troponin of keletal muscle fibers others are merely structural in nature; ex:  collagen and elastin D. NUCLEIC ACIDS - Play a vital role in protein synthesis - are nucleotide polymers (from the Greek word poly, meaning "several", and mer, meaning "unit"), that store and transmit genetic informatio of cell - Genetic information contained in nucleic acids is stored and replicated in chromosomes, which contain genes (from the Greek word gennan, meaning "to produce") - A chromosome is a deoxyribonucleic acid (DNA) molecule, and genes are segments of intact DNA. - When a cell replicates itself, identical copies of DNA molecules are produced, therefore the hereditary line of descent is conserved, and the genetic information carried on DNA is available to direct the occurrence of virtually all chemical reactions within the cell. - The flow of information from nucleic acids to protein: DNA —> messenger ribonucleic acid (mRNA) —> transfer RNA (tRNA) —> ribosomal RNA (rRNA) —> protein - The nucleotide sequence in a gene of DNA specifies the assembly of a nucleotide sequence in an mRNA molecule, which in turn directs the assembly of the amino acid sequence in protein through a tRNA and rRNA molecule B. INORGANIC COMPOUNDS - Water is an inorganic compound which is composed of hydrogen and oxygen. It is an important compound in the cell. THE IMPORTANCE OF WATER IN THE CELL - Water is important for life because its chemical and physical properties allow it to sustain life. - Water is a polar molecule which consists of 2 hydrogen atoms and 1 oxygen atom. A polar molecule is a molecule with an unequal distribution of charges. Each molecule has a positively charged and a negatively charged end. Polar molecules attract one another as well as ions. Because of this property, water is considered the solvent of life. - It is the transport medium in the blood - It acts as a medium for biochemical reactions. - Water helps in the maintenance of a stable internal environment within a living organism. The concentration of water and inorganic salts that dissolve in water is important in maintaining the osmotic balance between the blood and interstitial fluid. - It helps in lubrication. - Water molecules have very high cohesion. - Water molecules tend to stick to each other and move in long unbroken columns through the vascular tissues in plants. - Hydrogen, oxygen, nitrogen, carbon, sulfur, and phosphorus normally makeup more than 99% of the mass of living cells. Ninety-nine percent of the molecules inside living cells are water molecules. Cells generally contain many more protein molecules than DNA molecules, yet DNA is typically the largest biomolecule in the cell. REFERENCE: Chapter 1, Introduction to Human Anatomy/physiology (PDF) Introduction to Physiology: The Human Body. John P. Fisher, Adapted from Textbook of Medical Physiology, 11th Ed. Arthur C. Guyton, John E. Hall, Chapter 1 The chemical components of the cell. Haixu Tang. School of Informatics (PPT) NOTE: Some information were gathered online and others were from PDFs downloaded years ago. TYPE Digestive Enzymes Transport Structural Hormones Defense Contractile Storage EXAMPLES FUNCTIONS Amylase, Help in Lipase, Pepsin, digestion of Trypsin food by catabolizing nutrients into monomeric units Hemoglobin, Carry Albumin substances in the blood or lymph throughout the body Actin, Tubulin, Construct Keratin different structures like the cytoskeleton Insulin, Coordinate the Thyroxine activity of different body systems Immunoglobuli Protect the ns body from foreign pathogens Actin, Myosin Effect muscle contraction Legume storage Provide proteins, egg nourishment in white (albumin) early development of the embryo and the seedling Percenta ge of Body Weight 65% 18.6% 9.7% 3.2% 1.8% 1.0% Phosphor us This element is common in the bones and teeth, as well as nucleic acids. Element Usage 0.4% Potassium Potassium is found in the muscles, nerves, and certain tissues. Oxygen This element is obviously the most important element in the human body. Oxygen atoms are present in water, which is the compound most common in the body, and other compounds that make up tissues. It is also found in the blood and lungs due to respiration. 0.2% Sodium Sodium is excreted in sweat, but is also found in muscles and nerves. 0.2% Chlorine Chlorine is present in the skin and facilitates water absorption by the cells. Carbon is found in every organic molecule in the body, as well as the waste product of respiration (carbon dioxide). It is typically ingested in food that is eaten. 0.06% Magnesiu m Magnesium serves as a cofactor for various enzymes in the body. 0.04% Sulfur Sulfur is present in many amino acids and proteins. Iron Iron is found mostly in the blood since it facilitates the transportation of oxygen. Iodine Iodine is found in certain hormones in the thyroid gland. Carbon Hydrogen Hydrogen is found in all water molecules in the body as well as many other compounds making up the various tissues. Nitrogen Nitrogen is very common in proteins and organic compounds. It is also present in the lungs due to its abundance in the atmosphere. Calcium Calcium is a primary component of the skeletal system, including the teeth. It is also found in the nervous system, muscles, and the blood. 0.007% 0.0002 % CELLS - basic unit of life - all organisms are composed of cells - all living things are made up of cells - new cells arise only from preexisting cell - bounded by a selectively permeable membrane A. - PROKARYOTIC CELL Greek = before the nucleus single celled organism Bacteria and Cyanobacteria no nucleus DNA is not separated from other components Lack a membrane-bound nucleus Smaller than eukaryotic cells Have a single chromosome, semifluid cytoplasm, and thousands of ribosomes B. EUKARYOTIC CELL - greek = true nucleus - contain a well-defined nucleus surrounded by a nuclear membrane - can be single celled, such as yeast and paramecium, or multicellular, such as animals and plants - Cytoskeleton= protein fibers that maintain cell shape - Have membrane-bound nucleus and organelles *Endomembrane system: endoplasmic reticulum, Golgi apparatus, and lysosomes *Energy-related organelles: mitochondria and chloroplasts The cell is the structural and functional unit of all living organisms. It is made of three major parts: THE CELL'S PARTS 1. The plasma membrane 2. The cytoplasm 3. The nucleus A. THE PLASMA MEMBRANE (SKIN): - Cell Membrane - The plasma membrane (also called plasmalemma) forms the outer boundary of the cell - semi-permeable - It is the outer protective layer of cell. It isolates cell from neighbouring environment. - composed of proteins (structural; proteins) - a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell - The general structure of a biological membrane is a double layer of phospholipids FUNCTIONS: - maintains shape - contains the contents inside - prevents cell from mixing - controls entrance and exit of materials - protects the cell STRUCTURE: According to the "Fluid Mosaic Model Theory" postulated by Singer & Nicolson, the plasma membrane is composed mainly of phospholipids, proteins, and carbohydrates. 1. ) THE PHOSPHOLIPIDS - form a fluid "sea" made of a central bimolecular layer; here the long hydrophobic hydrocarbon chains of fatty acids (tails) are attached to the hydrophilic globular portions of phosphate (head). 2. ) THE PROTEINS - float like "icebergs" - Depending on their position they can be classified as: a.) Peripheral proteins- which associates to the globular portions of phospholipids. - they act as transporters or receptors b.) Integral proteins- which are attached to the hydrophobic portion. - they act as cytoskeleton anchors or enzymes 3. ) THE CARBOHYDRATES - consist of glycolipids and glycoproteins which form a filmy covering called the glycocalyx; it acts as: a.) an adhesive between cells. b.) site for immunological response c.) cell identity markers. 4. ) CHOLESTEROL - attached to phospholipid chains; it determines the fluidity of the plasma membrane. MOVEMENT ACROSS THE PLASMA MEMBRANES: - Two basic types of molecular traffic take place in and out of cells: passive movement and active movement 1. ) PASSIVE MOVEMENT - Molecules pass through the plasma membrane according to their concentration gradient (meaning from areas of high concentration to areas of low concentration without the use of energy (ATP)). Passive movement includes the following: a. ) DIFFUSION - random movement of molecules from areas where they are highly concentrated to areas where they are less concentrated until a uniform distribution of molecules is achieved. - (e.g.) inhaled O2 -> Lung -> Bloodstream b. ) FACILITATED DIFFUSION - when carrier proteins in the plasma membrane combine temporarily to molecules and allow them to pass through membrane via protein channels; they move from an area of high concentration to an area of low concentration. - (e.g.) - absorption of glucose or amino acids by the duodenum during digestion. c.) OSMOSIS - when water molecules move through a selectively permeable membrane from an area of high concentration of water to an area of low concentration of water.  Osmotic Pressure is the force exerted by a highly concentrated solution "A" which prevents the net flow of water across the selectively permeable membrane coming from a lower concentrated solution "B".  Osmotic pressure concept has its application in chemistry, biology, and medicine, and allows one to distinguish three types of solutions:  Hypotonic solution - when the solute concentration is lower outside the cell than it is inside the cell - (e.g.) when pure water is exposed to red blood cells (RBC), hemolysis occurs due the swelling and bursting of RBCs - -  Isotonic solution when the water and solute concentration outside the cell is the same as inside the cell. (e.g.) exposition of Red Blood Cells to a solution containing 0.85g of sodium chloride per 100 ml. water (physiological solution) does not result in the net movement of water into or out of the RBCs.  Hypertonic solution when the solute concentration is higher outside of the cell than it is inside. (e.g.) Exposition of RBCs in a solution containing 100g sodium chloride per 100 ml; results in crenation due to the loss of water by RBC and the shrinkage. d.) FILTRATION- Process that forces small particles dissolved in a solution to cross the s emipermeable membrane with the help of hydrostatic pressure. - (e.g.) Ultrafiltration of blood by the glomeruli of the kidneys e.) DIALYSIS- Exchange of solutes between two solutions separated by a semipermeable membrane - (e.g.) Use of the cellophane sheets in the artificial kidney machine is based upon this principle. 2. ) ACTIVE MOVEMENT - When substances move across a selectively permeable membrane from areas of low concentration to areas of high concentration. Since active movement is against the concentration gradient, it requires energy in the form of ATP. - Active movement includes the following: a.) active transport b.) exocytosis c.) endocytosis a. ) ACTIVE TRANSPORT - uses energy from the breakdown of ATP to move substances across selectively permeable membrane against a concentration gradient. - (e.g.) continuous transport of sodium out of resting cells by the "sodium-pump" even though its concentration is much higher outside of the cell. b. ) EXOCYTOSIS - is the fusion of secretory vesicles with the plasma membrane, followed by their expulsion from the cell through the plasma membrane. - (e.g. ) release of neurotransmitters by the neurons c.) ENDOCYTOSIS - process during which particles are engulfed by cytoplasmic extensions, thus forming membrane bound vesicles within the cytoplasm. - there are three types of endocytosis:  Pinocytosis - (also called "Cell Drinking") - is the process during which the plasma membrane invaginates and encloses small amounts of fluid droplets, thus forming small pockets which are released into the cytoplasm. (e.g. Kidney cells take in tissue fluids to maintain fluid balance). - a. ) AQUEOUS PHASE OR "FLUID PHASE" - consists of cytosol. The cytosol is composed of water (75% to 90%), proteins, carbohydrates, lipids, nucleic acids, and inorganic substances.  Receptor-mediated endocytosis - when extracellular large molecules bind with specific receptors on plasma membrane, causing the membrane to invaginate and draw them into the cytoplasm  Phagocytosis - called "Cell Eating" - is the ability of the plasma membrane to engulf large particles (foreign bodies, bacteria), and digesting them by fusing the pocket into which they are contained with lysosomal enzyme. (e.g. neutrophils digest harmful bacteria) B. - - CYTOPLASM (BLOOS) Cyto= Cell Plasm= fluid living substance of cell rich in organic and inorganic compounds is the portion of the cell located between the plasma membrane and the nucleus free floating Contains Organelles Source of energy is the mass of living matter between cell wall and nucleus. It contains stored foods, secretion granules, pigments and crystals. Stored foods are carbohydrates, fats, proteins, minerals and vitamins. Pigments are two types: a. ) ENDOGENOUS - pigments are haemoglobin and melanin b. ) EXOGENOUS - pigments are carotene from vegetables, dusts (carbon) and minerals (silver, lead etc.) It consists of an aqueous phase and an particulate phase: b. ) PARTICULATE PHASE - consist of organelles and inclusions:  - Endoplasmic Reticulum (ER) (Blood vessels) parallel arrays of canals attaches to the nuclear envelope transport of substances a membranous system where ribosomes attach and aid in protein synthesis is a network of tubes and flattened sacs that channels the flow of substances around the cytoplasm. is system that continues with infoldings of cell membrane and interlaces with the interior of cell Two types of "ER" are distinguishable: Smooth Endoplasmic Reticulum "SER" and Rough Endoplasmic Reticulum "RER". a. Smooth Endoplasmic Reticulum (SER) - is a delicate branching network of tubules free of ribosomes. - lacks proteins and is where lipids are made - is the site of steroids synthesis, especially steroid hormones (e.g. progesterone, estrogen, testosterone). - is involved in the degradation of hormones and drugs in the liver cells. - stores calcium in striated muscles. b. Rough Endoplasmic Reticulum (RER) - is a complex system of branching tubes and flattened sacs covered by ribosomes on their surface. - assists in protein synthesis and translation of language of nucleic acid  Cell Wall - extracellular structure that distinguishes plant cells from animal cells - protects the plant cell, maintains its shape, and prevents excessive uptake of water - Plant cell walls are made of cellulose fibers embedded in other polysaccharides and protein  Ribosomes - creates protein - non-membrane-bound particles where protein synthesis occurs - tiny spherical structures - are sites of protein synthesis - are spherical nonmembranous-bound organelles made of two subunits: (a.) The small ribosomal subunit. (b.) The large ribosomal subunit - are usually grouped in clusters in the cytoplasm and are then called polysomes  - Golgi Apparatus or Golgi Complex (Mouth) series of smooth membrane continuous with endoplasmic reticulum prepare materials for digestion packaging of food materials in preparation for digestion series of five to seven flattened sacs, involved in processing, storing, and packaging of secretory proteins. Composed of four or more stacked layers of thin, flat enclosed vesicles lying near the nucleus One side is directed toward the ER and t sorts and packages proteins and lipids in vesicles Prominent in secretory cells where it is located on the side of the cell from which secretory substances are released Golgi apparatus functions with the ER, where transport vesicles bud off the ER and diffuse to the Golgi apparatus – the Golgi apparatus processes ER vesicles to form lysosomes, - secretory vesicles, or other cytoplasmic components Involved in the formation of some large saccharide polymers bound with a small amount of protein, such as hyaluronic acid and chondroitin sulfate  Lysosomes (Stomach) - membrane-bound vesicles produced by the Golgi apparatus - Important in recycling cellular material and digesting worn-out organelles - Suicide bags with enzymes - secretes enzymes like hydrochloric acid to broken down nutrients and food materials and also viruses - Phagocytosis - membrane-bound organelles that contain digestive enzymes (acid hydrolase); act as the digestive system of the cell; also known as "suicide bags". - They contain powerful hydrolytic enzymes - are absent in RBC - Breaking down of particles taken in to cell and digestion - Autolysis - Phagocytosis - Killing of cells (planned way) - Cell division  - Centrosome cell center centrioles and asters (used for cell division) used in cell division  Peroxisomes - small, membrane-bound organelles resembling empty lysosomes - Contain enzymes to digest excess fatty acids *Produces products used by mitochondria to make ATP - Produce cholesterol and phospholipids found in brain and heart tissue - similar to lysosome - purine (end product) catabolism - converts fat into glucose (energy) - membrane-bound organelles found mostly in the liver, in the kidney and the macrophages contain enzymes (peroxidase) which are involved in the formation of hydrogen peroxide as they oxidize various substances.  Mitochondrion/ Mitochondria (Liver- secretes energy) - hotdog like, spherical, rod shaped, hollow structure - are the "powerhouses" of the cell because of ATP production. - provide energy; convert sugar into ATP (Adenosine Triphosphate) or enegry - provide site for synthesis of RNA and DNA - were also derived from bacteria and therefore have a double membrane - Double layered membrane organelle with its inner layer thrown into folds called "cristae" projecting into the inner cavity filled with amorphous substance called "matrix" where different enzymes are found. - are abundant in different types of cells such as myofibers, neurons, spermatozoa - Is the site of the final steps in cellular respiration, which result in the production of ATP used in the cell metabolic activities.  ATP - ATP means Adenosine Triphosphate - ATP is the main energy supplier for most biological activities in the cell. The phosphate bond (the P of ATP) is where most of the energy exists - Most of it is created in the cell's mitochondria.  - Microfilament (Fibers) Microscopic tubes made of contractile protein Locomotion  Cytoskeleton - Formed by: a. Microtubules b. Microfilaments c. ntermediate filaments - forms a supportive framework, assists in organelles movement, and provides a transport system within the cell.  Centrioles - A pair of cylindrical cytoplasmic organelles located in a space near the nucleus called centrosome - Assist in cell division by forming Mitotic Spindle System * Note that mitotic spindle is involved with chromosome movement during mitosis  Cilia - Minute cytoplasmic extensions from the cell which are involved in the transport of materials along the cell surface - hair like - whiplike structures of cells - (e.g. mucus movement in the trachea; movement of the ova in the fallopian tube.)  Flagellum - Cellular appendage which protrudes from the cell and allows its propulsion - tail of sperm cell - (e.g. Spermatozoa tail is made of flagellum)  Secretory Vesicles - Membrane bound cytoplasmic chambers containing products of secretion such as protein.  Microtubules (Spine) - made up of protein molecules  Cytoplasmic Inclusions - There is a variety of cellular inclusions. Examples are: a. Lipid droplets - storage for energy b. Glycogen - principal storage form of carbohydrates c. Zymogen granules - secretory products rich in inactive enzyme d. Melanin pigment - most abundant skin pigment e. Hemosiderin - yellowish brown pigment resulting from degradation of hemoglobin  Centrosome - Centrosome contains centrioles. Centrioles control polarisation of spindle fibres. Centriole is closely related to spindle formation during cell division (Mitosis).  Plasmosin - is constant constituent of cytoplasm. They form Tonofibrils in epithelial cells, myofibrils in muscles and neurofibrils in nerves. - They consist of long protein molecules rich in deoxy -ribonucleoprotein.  - Vacuoles spherical empty sacs storage food They are also cytoplasmic organelles. They are found covered by fat on staining with dilute neutral red solution. membranous sacs larger than vesicles and usually store substances Example: toxic substances used in plant defense Central vacuole – found in plants, contains watery sap and maintains turgor pressure  Nasal bodies - They are found in nerve cells.  Secretory granules - They store secretory products of cell and are found in- Golgi apparatus and E.R C. - THE NUCLEUS (BRAIN) rounded darkly stained object inside the cell key structure of living cell control center/ controls all the processes of organelles - controls protein synthesis (production of protein) - The nucleus is the container of DNA in eukaryotic cells Site where the genetic material is stored It consists of three components: 1. NUCLEAR MEMBRANE OR NUCLEAR ENVELOPE - Separates the nucleus from the cytoplasm. - Contains opening called nucleopores which are potential passageway for exchange of substances (e.g.) Messenger Ribonucleic Acid (mRNA) 2. CHROMATIN - Complex substance made up fibrous strands containing DNA and proteins. DNA controls: a.) Cell's Heredity b.) Protein Structure c.) Other nonmetabolic activity 3. NUCLEOLUS - Dense nonmembranous mass where RNA is synthesized; location for the components found in ribosomes. * Note: Red Blood Cells (RBC) in circulation don't have a nucleus; therefore, they are unable to divide and they die after 4 months in circulation ADDITIONAL: A. CHROMOSOMES - Chromosomes are present as individual bodies in interphase as well as in mitosis. Predominant component in chromosome is DNA. - Genes are located in chromosome. They are discrete units of transmission of hereditary characters. B. CHLOROPLASTS type of plastid, an organelle bounded by a double membrane with a series of internal membranes separated by a ground substance - site of photosynthesis - Other plastids are:  Chromoplast- contain variously colored pigments like red, blue, violet, yellow etc.  Leukoplast- colorless plastid; storage depot of starch C. PRESENCE OF CAPSULE IN BACTERIA = harmful D. KIDNEY - steriles; does not have bacteria E. URINE - is sterile since it came from kidney REFERENCE: Chapter 1, Introduction to Human Anatomy/physiology (PDF) Introduction to Human Anatomy. The Medical Lab Technician (PDF) Introduction to Physiology: The Human Body. John P. Fisher, Adapted from Textbook of Medical Physiology, 11th Ed. Arthur C. Guyton, John E. Hall, Chapter 1 https://twitter.com/student_nxrs/status/1036502465493889 024?s=21&fbclid=IwAR2licQH2zbPdPMLCIBX4BOWDgL6G9h NBdtizO2-JF6fHEPBtxh_I452mPk NOTE: Some information were gathered online and others were from PDFs downloaded years ago. PROKARYOTE EUKARYOTE No nucleus With nucleus DNA is not separated from other components Small and simple DNA is separated by membrane bound Have organelles Can be unicellular or multicellular Have cytoskeleton No organelles Are very abundant All are unicellular Cells have a sticky capsule All cells have cell walls Were the first cells Live a wide variety of environments All are bacteria Not found in humans Reproduce/ divide by binary fission Some have cilia Includes everything that’s not bacteria Found in humans Reproduce/divi de by meiosis/mitosis BOTH Have ribosomes Have DNA Have cytoplasm Have cell membrane Have flagella THREE TYPES OF OSMOTIC SOLUTIONS A. ISOTONIC: - equal. Water moves in and out of the cell at an equal rate B. HYPOTONIC CELL PHYSIOLOGY - is the biological study about the activities that take place in a cell to keep it alive. In the context of human physiology, the term cell physiology often specifically applies to the physiology of membrane transport, neuron transmission, and (less frequently) muscle contraction. * Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. OSMOSIS - Osmosis movement of a solvent (such as water) through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane. *It does not require energy to be applied water moves into the cell, making it swell and get fat. There is a greater concentration or number of solute particles inside a membrane than there are outside. C. HYPERTONIC - water moves outside the cell, making it shrink. There is a greater concentration or number of solute particles outside a membrane than there are inside. DIFUSSION - Diffusion is the net movement of particles from an area of higher concentration to lower concentration. TWO MAIN TYPES OF DIFFUSION: A. PASSIVE DIFFUSION - is the movement of molecules across a semi-permeable membrane without the help of protein channels. B. FACILITATED DIFFUSION - is the flow of molecules down a concentration gradient, across a membrane, but requires the help of a protein. There are two categories of proteins that assist facilitated diffusion:  CARRIER PROTEINS- are like taxi cabs in a cell membrane  CHANNEL PROTEINS- are like tunnels that create a hole across a cell membrane. Channels open to allow molecules to flow through them.  PINOCYTOSIS- brings liquids into the cell  PHAGOCYTOSIS- is responsible for transporting large particles or other solids into the cell C. EXOCYTOSIS DIFFERENCES BETWEEN OSMOSIS AND DIFFUSION: Osmosis- is a slow process and diffusion is the fast process. Osmosis is dependent on one solvent to the another for the reduction of free energy Diffusion- the movement of molecules is from the area of their higher free energy to the area of the lower free energy ACTIVE TRANSPORT - a protein pump uses energy, in the form of ATP, to move molecules from an area of low concentration to an area of high concentration. - is very similar to endoxytosis except that it deposits materials from inside the cell on the outside instead of the other way around PASSIVE TRANSPORT - is a movement of ions and other atomic or molecular substances across cell membranes without need of energy input. THREE MAIN TYPES OF PASSIVE TRANSPORT: A. SIMPLE DIFFUSION - movement of small or lipophilic molecules B. OSMOSIS 3 MAIN TYPES OF ACTIVE TRANSPORT: - A. SODIUM-POTASSIUM PUMP C. FACILITATED DIFFUSION - - is a structure known as a cell-membrane pump that uses energy to transport Sodium and Potassium ions in and out of the cell. movement of water molecules movement of large or charged molecules via membrane proteins B. ENDOCYTOSIS - is a process by which cells can take in large particles and deposit them into the cell There are 2 sub-categories: CELL DIVISION - Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle. THE CELL CYCLE - It is the period between the beginning of one cell division and the beginning of the next cell division. - There are two types of cell division: somatic and reproductive. TYPES OF CELL DIVISION: A. MITOSIS - - is a fundamental process for life. During mitosis, a cell duplicates all of its contents, including its chromosomes, and splits to form two identical daughter cells. Mitosis has five different stages: A. SOMATIC CELL DIVISION (BODY CELL DIVISION) - 1. Interphase 2. Prophase 3. Metaphase 4. Anaphase 1. ) INTERPHASE - 5. Telophase - The process of cell division is only complete after cytokinesis, which takes place during anaphase and telophase. Each stage of mitosis is necessary for cell replication and division B. MEIOSIS - Meiosis ensures that humans have the same number of chromosomes in each generation. It is a two-step process that reduces the chromosome number by half—from 46 to 23—to form sperm and egg cells. When the sperm and egg cells unite at conception, each contributes 23 chromosomes so the resulting embryo will have the usual 46. Meiosis also allows genetic variation through a process of DNA shuffling while the cells are dividing. It involves three major process: Interphase, Mitosis, and Cytokinesis. Is a very active period of cell activity during which DNA in the nucleus doubles. The phenomenon is called "Replication", meaning that DNA makes the copy of itself. 2. ) CYTOKINESIS - division of the cytoplasm into two distinct daughter cells. 3. ) MITOSIS - is the process during which two diploid (2n) daughter cells result from the division of a diploid (2n) parent cell. - in human daughter cells, n = 23 chromosomes from each parent. - It is divided into four sequential stages:  PROPHASE - the first stage of mitosis; it is the longest mitotic phase. a. Early Prophase- Chromatin condenses and shortens into chromosomes. -Each prophase chromosome has a pair of identical, double-stranded DNAs called Chromatids b. Late Prophase- Disappearance of the Nucleoli - Chromosomes uncoil and become chromatin - formation of nuclear membrane around each set of chromatin. - appearance of nucleoli - Mitotic apparatus disappears. - formation of two daughter cells with 46 chromosomes each B. REPRODUCTIVE CELL DIVISION OR MEIOSIS - occurs only in the gonads (testes & ovaries) and results in the formation of mature gametes (spermatozoa in the male and ova in the female) - starts at the onset of puberty and continues during the entire lifetime in the male; stops during menopause in the female. - unlike the somatic cell division, meiosis is characterized by the formation of haploid (n chromosome) daughter cells resulting from the division of the diploid (2n chromosome) parent cell. Thus, each daughter cell contains only 23 chromosomes. - Meiosis consists of two steps: first meiotic division (reduction) and second meiotic division (equatorial) - breakdown of the nuclear membrane - Movement of the two centrioles toward opposite directions. - Appearance of mitotic apparatus  METAPHASE - the second mitotic stage; the chromatid pairs line up at the center of mitotic apparatus.  ANAPHASE - the third stage. - shortest mitotic phase - movement of the two sister chromatids of each chromosomes toward opposite pole of the cell.  TELOPHASE - the fourth mitotic stage 1. ) FIRST MEIOTIC DIVISION  METAPHASE II - is composed of four sequential phases: -  PROPHASE I - appearance of double stranded chromosomes. Pairing of homologous chromosomes lie side by side single chromosome lines up at the center of the mitotic apparatus.  ANAPHASE II - migration of the chromatid of each chromosome to opposite poles.  METAPHASE I  TELOPHASE II - - pairs of homologous chromosomes line up at the center of mitotic apparatus production of two haploid cells from each haploid cell of the telophase I.  ANAPHASE I REFERENCE: - Chapter 1, Introduction to Human Anatomy/physiology (PDF) one chromosome of each homologous pair migrates to opposite poles.  TELOPHASE I - two haploid (n chromosome) daughter cells result from the division of a diploid (2n chromosome) parent cell 2. ) SECOND MEIOTIC DIVISION - is the continuation of the first meiotic division and is also subdivided into four phases  PROPHASE II - Each chromosome of the haploid daughter cell resulting from the first meiotic division has two chromatids Introduction to Physiology: The Human Body. John P. Fisher, Adapted from Textbook of Medical Physiology, 11th Ed. Arthur C. Guyton, John E. Hall, Chapter 1 NOTE: Some information were gathered online and others were from PDFs downloaded years ago. - the membranes always have one free (unattached) surface or edge. This apical surface is exposed to the body’s exterior or to the cavity of an internal organ. The exposed surfaces of some epithelia are slick and smooth, but others exhibit cell surface modifications, such as microvilli or cilia. the anchored (basal) surface of epithelium rests on a basement membrane, a structureless material secreted by both the epithelial cells and the connective tissue cells deep to the epithelium. Think of the basement membrane as the “glue” holding the epithelium in place. Epithelial tissues have no blood supply of their own (that is, they are avascular) and depend on diffusion from the capillaries in the underlying connective tissue for food and oxygen. If well nourished, epithelial cells regenerate themselves easily. TISSUE - group of cells that are similar in structure and function and represent the next level of structural organization - contributes to the functioning of the organs in which it is found. - are organized into organs such as the heart, kidneys, and lungs - the four primary tissue types interweave to form the fabric of the body 1. Epithelial (covering) 2. Connective (support) 3. Muscle (movement) 4. Nervous (control) - 1. EPITHELIAL TISSUE - or Epithelium - the lining, covering, and glandular tissue of the body - Covering and lining epithelium covers all free body surfaces, both inside and out, and contains versatile cells. - its functions include protection, absorption, filtration, and secretion - Glandular epithelium forms various glands in the body - Secretion is a specialty of the glands, which produce such substances as sweat, oil, digestive enzymes, and mucus CLASSIFICATION OF EPITHELIA CHARACTERISTICS OF EPITHELIUM - Except for glandular epithelium, epithelial cells fit closely together to form continuous sheets. Neighboring cells are bound together at many points by specialized cell junctions, including desmosomes and tight junctions - - CELL ARRANGEMENT (LAYERS) Terms Description Simple Epithelium One layer of cells Stratified Epithelium More than one cell layer SHAPE OF ITS CELLS Squamous Cells Flattened like fish scale Cuboidal Cells Cube-shaped like dice Columnar Cells Shaped like columns Transitional The terms describing the shape and arrangement are then combined to describe the epithelium fully. a. SIMPLE EPITHELIA - are most concerned with absorption, secretion, and filtration  SIMPLE SQUAMOUS EPITHELIUM - a single layer of thin squamous cells resting on a basement membrane - the cells fit closely together - it usually forms membranes where filtration or exchange of substances by rapid diffusion occurs - it is in the air sacs of the lungs (called alveoli), where oxygen and carbon dioxide are exchanged - it forms the walls of capillaries, where nutrients and gases pass between the blood in the capillaries and the interstitial fluid - it also forms serous membranes or serose which is the slick membranes that line the ventral body cavity and cover the organs in the cavity  SIMPLE CUBOIDAL EPITHELIUM - it rests on a basement membrane - it makes up the functional units of the thyroid gland and salivary glands - it is common in glands and their associated small tubes called ducts - it also forms the walls of the kidney tubules and covers the surface of the ovaries.  SIMPLE COLUMNAR EITHELIUM - is made up of a single layer of tall cells that fit closely together - are specialized for secretion and absorption - Goblet cells, which produce a lubricating mucus, are often seen in this type of epithelium - it lines the entire length of the digestive tract from the stomach to the anus - Epithelial membranes that line body cavities open to the body exterior are called mucosae or mucous membranes  PSEUDOSTRATIFIED COLUMNAR EPITHELIUM - all of the cells rest on a basement membrane. However, some of its cells are shorter than others, and their nuclei appear at different heights above the basement membrane. As a result, this epithelium gives the false (pseudo) impression that it is stratified; hence its name - like simple columnar epithelium, this variety mainly functions in absorption and secretion - a ciliated variety (more precisely called pseudostratified ciliated columnar epithelium) lines most of the respiratory tract - the mucus produced by the goblet cells in this epithelium acts as a “sticky trap” to catch dust and other debris, and the cilia propel the mucus upward and away from the lungs b. STRATIFIED EPITHELIA - it consist of two or more cell layers consists of many layers of mostly flat cells, although lower cells are rounded - being considerably more durable than the simple epithelia, these epithelia function primarily in protection  STRATIFIED SQUAMOUS EPITHELIUM - it is the most common stratified epithelium in the body - it usually consists of many cell layers. The cells at the free edge are squamous cells, whereas those close to the basement membrane are cuboidal or columnar. - it is found in sites that receive a good deal of abuse or friction, such as the surface of the skin, the mouth, and the esophagus - this type of epithelium makes up the epidermis of the skin, where it is called “keratinizing” because the protein keratin is produced, and the surface cells are dead - Stratified squamous epithelium of the non-keratinizing type lines the oral cavity, the esophagus, and, in women, the vagina  STRATIFIED CUBOIDAL AND STRATIFIED COLUMNAR EPITHELIA - Stratified cuboidal epithelium typically has just two cell layers with (at least) the surface cells being cuboidal in shape. - the surface cells of stratified columnar epithelium are columnar cells, but its basal cells vary in size and shape - both of these epithelia are fairly rare in the body, found mainly in the ducts of large glands  TRANSITIONAL EPITHELIUM - is a highly modified, stratified squamous epithelium that forms the lining of only a few organs—the urinary bladder, the ureters, and part of the urethra - As part of the urinary system, all of these organs are subject to considerable stretching - cells of the basal layer are cuboidal or columnar; those at the free surface vary in appearance. - when the organ is not stretchd, the membrane is many-layered, and the superficial cells are rounded and domelike. - when the organ is distended with urine, the epithelium thins like a rubber band being stretched, and the surface cells flatten and become squamouslike - this ability of transitional cells to slide past one another and change their shape (undergo “transitions”) allows the ureter wall to stretch as a greater volume of urine flows through that tubelike organ. In the bladder, it allows more urine to be stored ADDITIONAL:  GRANDULAR EPITHELIUM - - A gland consists of one or more cells that make and secrete a particular product. This product, a secretion, typically contains protein molecules in an aqueous (water -based) fluid. The term secretion also indicates an active process in which the glandular cells obtain needed materials from the blood and use them to make their products, which they then discharge by exocytosis. Two major types of glands develop from epithelial sheets: a. Endocrine glands - lose their ducts; thus they are often called ductless glands. Their secretions (all hormones) diffuse directly into the blood vessels that weave through the glands - Examples of endocrine glands include the thyroid, adrenals, and pituitary b. Exocrine glands - it retain their ducts, and their secretions exit through the ducts to the epithelial surface - Exocrine glands, which include the sweat and oil glands, liver, and pancreas, are both internal and external.  ENDOTHELIUM - the inner lining of blood vessels, the heart, and lymphatic vessels) is a specialized form of epithelium - with a single layer of squamous cells attached to a basement membrane 2. CONNECTIVE TISSUE - it is the most abundant and widely distributed of the tissue types - it performs many functions, but they are primarily involved in protecting, supporting, and binding together other body tissues CHARACTERISTICS OF CONNECTIVE TISSUE - Variations in blood supply. Most connective tissues are well vascularized (that is, they have a good blood supply), but there are exceptions. Tendons and ligaments, for example, have a poor blood supply, and cartilages are avascular. Consequently, all these structures heal very slowly when injured - Extracellular matrix. Connective tissues are made up of many different types of cells plus varying amounts of a nonliving substance found outside the cells, called the extracellular matrix. *Extracellular Matrix- the matrix, which is produced by the connective tissue cells and then secreted to their exterior, has two main elements, a structureless ground substance and fibers TYPES OF CONNECTIVE TISSUE  BONE - sometimes called osseous tissue - it is composed of osteocytes sitting in cavities called lacunae. These pits are surrounded by layers of a very hard matrix that contains calcium salts in addition to large numbers of collagen fibers - because of its rocklike hardness, bone has an exceptional ability to protect and support other body organs (for example, the skull protects the brain)  CARTILAGE - is less hard and more flexible than bone. - its major cell type is chondrocytes (cartilage cells) - it is found in only a few places in the body. - most widespread is hyaline (hi′ah-lin) cartilage, which has abundant collagen fibers hidden by a rubbery matrix with a glassy (hyalin = glass), blue-white appearance - it forms the trachea, or windpipe, attaches the ribs to the breastbone, and covers bone ends at joints - although hyaline cartilage is the most abundant type of cartilage in the body, there are others - highly compressible fibrocartilage forms the cushionlike disks between the vertebrae of the spinal column - elastic cartilage is found in structures with elasticity, such as the external ear  DENSE CONNECTIVE TISSUE - also called dense fibrous tissue - the collagen fibers are the main matrix element - crowded between the collagen fibers are rows of fibroblasts (fiber-forming cells) that manufacture the building blocks of the fibers. - it forms strong, ropelike structures such as tendons and ligaments. Tendons attach skeletal muscles to bones; ligaments connect bones to bones at joints. Ligaments are more stretchy and contain more elastic fibers than do tendons - this also makes up the lower layers of the skin (dermis), where it is arranged in sheets  LOOSE CONNECTIVE TISSUE - are softer and have more cells and fewer fibers than any other connective tissue type except blood - there are three main types of loose connective tissue: areolar, adipose, and reticular. a. Areolar connective tissue - the most widely distributed connective tissue variety in the body, is a soft, pliable, “cobwebby” tissue that cushions and protects the body organs it wraps. It functions as a universal packing tissue and connective tissue “glue” because it helps to hold the internal organs together and in their proper positions. b. Adipose Connective Tissue - is commonly called fat. It is an areolar tissue in which adipose (fat) cells predominate. Adipose tissue forms the subcutaneous tissue beneath the skin, where it insulates the body and protects it from bumps and extremes of both heat and cold. Adipose tissue also protects some organs. c. Reticular Connective Tissue - it consists of a delicate network of interwoven reticular fibers associated with reticular cells, which resemble fibroblasts. Reticular tissue is limited to certain sites: It forms the stroma (literally, “bed” or “mattress”), or internal framework of an organ. The stroma can support many free blood cells (largely white blood cells called lymphocytes) in lymphoid organs. It may help to think of reticular tissue as “cellular bleachers” where other cells can observe their surroundings  BLOOD - or vascular tissue, is considered a connective tissue because it consists of blood cells surrounded by a nonliving, fluid matrix called blood plasma, which is about 52% to 62% of the total blood volume in the body - the “fibers” of blood are soluble proteins that become visible only during blood clotting. Still, blood is quite atypical as connective tissues go. - blood is the transport vehicle for the cardiovascular system, carrying nutrients, wastes, respiratory gases, white blood cells, and many other substances throughout the body. TYPE TYPES OF CONNECTIVE TISSUE LOCATION STRUCTURE Blood Areolar (loose) Adipose Fibrous Elastic Plasma (matrix) and red blood cells, white blood cells, and platelets Fibroblasts and a matrix of tissue flfluid, collagen, and elastin fibers Adipocytes that store fat (little matrix) Mostly collagen fibers (matrix) with few fibroblasts Mostly elastin fibers (matrix) AND FUNCTION Within blood vessels •Plasma—transports materials • RBCs—carry oxygen • WBCs—destroy pathogens • Platelets—prevent blood loss Subcutaneous • Connects skin to muscles; WBCs destroy pathogens Mucous membranes (digestive, respiratory, urinary, reproductive tracts) • WBCs destroy pathogens Subcutaneous • Stores excess energy • Produces chemicals that influence appetite, use of nutrients, and inflammation Around eyes and Kidneys • Cushions Tendons and ligaments (regular) • Strong to withstand forces of movement of joints Dermis (irregular) • The strong inner layer of the skin Walls of large arteries with few fibroblasts Bone Cartilage Osteocytes in a matrix of calcium salts and collagen Chondrocytes in a flexible protein matrix • Helps maintain blood pressure Around alveoli in lungs • Promotes normal exhalation Bones • Support the body • Protect internal organs from mechanical injury • Store excess calcium • Contain and protect red bone marrow Wall of trachea • Keeps airway open On joint surfaces of bones • Smooth to prevent friction Tip of nose and outer ear • Support Between vertebrae • Absorb shock 3. MUSCLE TISSUE - are highly specialized to contract, or shorten, which generates the force required to produce movement. - There are three types of muscle tissue: skeletal, cardiac, and smooth  SKELETAL MUSCLE TISSUE - also called as striated or voluntary muscle - is packaged by connective tissue sheets into organs called skeletal muscles, which are attached to the skeleton’ - these muscles, which can be controlled voluntarily or consciously, form the flesh of the body, the so-called muscular system - when the skeletal muscles contract, they pull on bones or skin. As a result, gross body movements or changes in our facial expressions occur - the cells of skeletal muscle are long, cylindrical, and multinucleate, and they have obvious striations (stripes). Because skeletal muscle cells are elongated to provide a long axis for contraction, they are often called muscle fibers.  CARDIAC MUSCLE - is found only in the heart wall. As it contracts, the heart acts as a pump to propel blood through the blood vessels. - like skeletal muscle, it has striations, but cardiac cells have only a single nucleus and are relatively short, branching cells that fit tightly together (like clasped fingers) at junctions called intercalated discs. - Cardiac muscle is under involuntary control, which means that we cannot consciously control the activity of the heart.  SMOOTH (VISCERAL) MUSCLE - is so called because no striations are visible - also called as involuntary muscle - the individual cells have a single nucleus and are tapered at both ends. - this is found in the walls of hollow organs such as the stomach, uterus, and blood vessels. - as smooth muscle in its walls contracts, the cavity of an organ alternately becomes smaller (constricts when smooth muscle contracts) or enlarges (dilates when smooth muscle relaxes) so that substances are mixed and/or propelled through the organ along a specific pathway. - Smooth muscle contracts much more slowly than the other two muscle types, and these contractions tend to last longer - Peristalsis, a wavelike motion that keeps food moving through the small intestine, is typical of its activity. tissue, that is, by the formation of scar tissue. occurs depends on (1) the type of tissue damaged and (2) the severity of the injury. clean cuts (incisions) heal much more successfully than ragged tears of the tissue. Tissue injury sets the following series of events into motion: 4. NERVOUS TISSUE - All neurons receive and conduct electrochemical impulses from one part of the body to another; thus, irritability and conductivity are their two major functional characteristics - the structure of neurons is unique; their cytoplasm is drawn out into long processes (extensions), as long as 3 feet or more in the leg, which allows a single neuron to conduct an impulse to distant body locations. - the nervous system is more than just neurons. A special group of supporting cells called neuroglia insulate, support, and protect the delicate neurons in the structures of the nervous system—the brain, spinal cord, and nerves. - TISSUE REPAIRING (WOUND HEALING) - Intact physical barriers such as the skin and mucous membranes, cilia, and the strong acid produced by stomach glands are just three examples of body defenses exerted at the tissue level - When tissue injury does occur, it stimulates the body’s inflammatory and immune responses, and the healing process begins almost immediately - Inflammation is a general (nonspecific) body response that attempts to prevent further injury - The immune response, in contrast, is extremely specific and mounts a vigorous attack against recognized invaders, including bacteria, viruses, and toxins. - Tissue repair, or wound healing, occurs in two major ways: Essentials of Anatomy and Physiology 5th Edition. Scanlon, V.C. & Sanders, T., 2007. F.A. Davis Company, Philadelphia. (PDF)  REGENERATION - is the replacement of destroyed tissue by the same kind of cells, whereas fibrosis involves repair by dense (fibrous) connective - • Inflammation sets the stage • Granulation tissue forms • Regeneration and fibrosis effect permanent repair REFERENCE Essentials of Human Anatomy & Physiology 12th Edition. Marieb, E.N & Keller, 2016. S.M. Boston : Pearson. (PDF) - BODY MEMBRANE - cover surfaces, line body cavities, and form protective (often lubricating) sheets around organs - fall into two major groups: A. EPITHELIAL MEMBRANES - also called covering and lining membranes - include the cutaneous membrane (skin), the mucous membranes, and the serous membranes - Although they all do contain an epithelial layer, it is always combined with an underlying layer of connective tissue. Hence these membranes are actually simple organs 1. CUTANEOUS MEMBRANE - generally called the skin or integumentary system - the outer covering that wee rely on for protection - membrane is exposed to air and is a dry membrane - composed of two layers:  Epidermis- composed of stratified squamous epithelium  Dermis- mostly dense (fibrous) connective tissue. 2. MUCOUS MEMBRANES - composed of epithelium (the type varies with the site) resting on a loose connective tissue membrane called a lamina propria - this membrane type lines all body cavities that open to the exterior, such as those of the hollow - organs of the respiratory, digestive, urinary, and reproductive tracts the term mucosa refers only to the location of the epithelial membranes, not their cellular makeup, which varies. most mucosae contain either stratified squamous epithelium or simple columnar epithelium In all cases, they are moist membranes that are almost continuously bathed in secretions or, in the case of the urinary mucosae, urine. The epithelium of mucosae is often adapted for absorption or secretion. Although many mucosae secrete mucus, not all do. The mucosae of the respiratory and digestive tracts secrete large amounts of protective, lubricating mucus; that of the urinary tract does not. 3. SEROUS MEMBRANES - or serosa, is composed of a layer of simple squamous epithelium resting on a thin layer of areolar connective tissue - serous membranes line body cavities that are closed to the exterior (except for the dorsal body cavity and joint cavities) - occur in pairs:  Parietal layer- lines a specific portion of the wall of the ventral body cavity. It folds in on itself to form the  Visceral layer- covers the outside of the organ(s) in that cavity. - In the body, the serous layers are separated not by air but by a scanty amount of thin, clear fluid, called serous fluid, which is secreted by both membranes - Although there is a potential space between the two membranes, they tend to lie very close to each other. The lubricating serous fluid allows the organs to slide easily across the cavity walls and one another without friction as they carry out their routine functions - the specific names of the serous membranes depend on their locations. The serosa lining the abdominal cavity and covering its organs is the peritoneum - In the thorax, serous membranes isolate the lungs and heart from one another. The membranes surrounding the lungs are the pleurae; those around the heart are the pericardia B. CONNECTIVE TISSUE MEMBRANES 1. SYNOVIAL MEMBRANES - composed of loose areolar connective tissue and contain no epithelial cells at all - these membranes line the fibrous capsules surrounding joints, where they provide a smooth surface and secrete a lubricating fluid - they also line small sacs of connective tissue called bursae and the tubelike tendon sheaths INTEGUMENTARY SYSTEM - includes body membranes, skin, hair, fingernails, and sweat and oil glands - also called the integument which simply means “covering” - most, but not all, of which are protective - It insulates and cushions the deeper body organs and protects the entire body from  mechanical damage (bumps and cuts)  chemical damage (such as from acids and bases)  thermal damage (heat and cold)  ultraviolet (UV) radiation (in sunlight), and  microbes - the uppermost layer of the skin is hardened, to help prevent water loss from the body surface - the skin’s rich capillary network and sweat glands (both controlled by the nervous system) play an important role in regulating heat loss from the body surface - the skin acts as a mini-excretory system; urea, salts, and water are lost when we sweat a chemical plant; it manufactures several proteins important to immunity and synthesizes vitamin D - also produces acidic secretions, called the acid mantle, that protect against bacterial invasion. SKIN - has multiple layers that protect the body, help regulate body temperature, and help excrete wastes via sweat - is the first barrier to keep good things such as water in, and bad things such as harmful bacteria out - absolutely essential because it keeps water and other precious molecules in the body - it keeps excess water (and other things) out - structurally, the skin is a marvel. It is pliable yet tough, which allows it to take constant punishment from external agents STRUCTURE OF THE SKIN A. EPIDERMIS - made up of stratified squamous epithelium that is capable of becoming hard and tough - Most of its cells are keratinocytes which produce keratin, the fibrous protein that makes the epidermis a tough protective layer in a process called keratinization. These keratinocytes are connected by desmosomes throughout the epidermis - is avascular; that is, it has no blood supply of its own - composed of up to five layers, or strata - From the inside out these are the stratum basale, spinosum, granulosum, lucidum, and corneum 1. STRATUM BASALE - deepest cell layer of epidermis - lies closest to the dermis and is connected to it along a wavy border that resembles corrugated cardboard - contains the most adequately nourished of the epidermal cells because nutrients diffusing from the dermis reach them first - stem cells in this layer are constantly dividing, and millions of new cells are produced daily; hence its alternate name, stratum germinativum - of the new cells produced, some become epidermal cells, and others maintain the population of stem cells by continuing to divide. The daughter cells destined to become epidermal cells are pushed upward, away from the source of nutrition, to become part of the epidermal layers closer to the skin surface. 2. STRATUM SPINOSUM - the cells which is move away from the dermis become part of this layer 3. STRATUM GRANULOSUM - epidermis cells becomes flatter and increasingly keratinized 4. STRATUM LUCIDUM - as the cells leave the stratum granulosum, they die, then form the clear stratum lucidum - not present in all skin regions. It occurs only where the skin is hairless and extra thick, that is, on the palms of the hands and soles of the feet - the combination of accumulating keratin inside them, secreting a water-repellent glycolipid into the extracellular space, and their increasing distance from the blood supply (in the dermis) effectively dooms the stratum lucidum cells and the more superficial epidermal cells because they are unable to get adequate nutrients and oxygen. 5. STRATUM CORNEUM - is 20 to 30 cell layers thick, but it accounts for about three-quarters of the epidermal thickness - the shinglelike dead cell remnants, completely filled with keratin, are referred to as cornified or horny cells - the abundance of the tough keratin protein in the stratum corneum allows that layer to provide a durable “overcoat” for the body, which protects deeper cells from the hostile external environment and from water loss, and helps the body resist biological, chemical, and physical assaults - it rubs and flakes off slowly and steadily as the dandruff familiar to everyone - this layer is replaced by cells produced by the division of the deeper stratum basale cells - we have totally “new” epidermis every 25 to 45 days. *Melanin - a pigment that ranges in color from yellow to brown to black - is produced by special spider-shaped cells called melanocytes found chiefly in the stratum basale - Freckles and moles are seen where melanin is concentrated in one spot. *Epidermal dendritic cells- scattered in the epidermis which are important “sentries” that alert and activate immune system cells to a threat such as bacterial or viral invasion *Merkel cells- seen here and there at the epidermal-dermal junction which are associated with sensory nerve endings and serve as touch receptors called Merkel discs B. - - DERMIS made up mostly of dense connective tissue varies in thickness a strong, stretchy envelope that helps to bind the body together the epidermis and dermis are firmly connected and the dermis is fairly tear resistant. However, a burn or friction may cause them to separate, allowing interstitial fluid to accumulate in the cavity between the layers, which results in a blister is abundantly supplied with blood vessels that play a role in maintaining body temperature homeostasis When body temperature is high, the capillaries of the dermis become engorged, or swollen, with heated blood, and the skin becomes reddened and warm. This allows body heat to radiate from the skin surface. If the environment is cool and body heat must be - conserved, blood bypasses the dermis capillaries temporarily, allowing internal body temperature to remain high. has a rich nerve supply made up of dense connective tissue which are composed of areolar and dense irregular connective tissue, respectively, and has 2 regions: 1. PAPILLARY - the superficial dermal region - It is uneven and has peglike projections from its superior surface, called dermal papillae which indent the epidermis above. Many of the dermal papillae contain capillary loops, which furnish nutrients to the epidermis - On the palms of the hands and soles of the feet, the papillae are arranged in definite patterns that form looped and whorled ridges on the epidermal surface that increase friction and enhance the gripping ability of the fingers and feet - Papillary patterns are genetically determined. The ridges of the fingertips are well provided with sweat pores and leave unique, identifying films of sweat called fingerprints on almost anything they touch 2. RETICULAR - the deepest skin layer - It contains dense irregular connective tissue, as well as blood vessels, sweat and oil glands, and deep pressure receptors called lamellar corpuscles - Other cutaneous sensory receptors, which are actually part of the nervous system, are also located in the skin. These tiny sensors, which include touch, pressure, temperature, and pain receptors, provide us with a great deal of information about our external environment - Phagocytes found here act to prevent microbes that have managed to get through the epidermis from penetrating any deeper into the body - both collagen and elastic fibers are found throughout the dermis. *Collagen fibers- are responsible for the toughness of the dermis; they also attract and bind water and thus help to keep the skin hydrated. *Elastic fibers- give the skin its elasticity when we are young. As we age, the number of collagen and elastic fibers decreases, and the subcutaneous tissue loses fat. As a result, the skin loses its elasticity and begins to sag and wrinkle. SUBCUTANEOUS TISSUE, or HYPODERMIS - the deep part of the dermis which essentially is adipose (fat) tissue. It is not considered part of the skin, but it does anchor the skin to underlying organs and provides a site for nutrient storage. SKIN COLOR - three pigments: 1. MELANIN - the amount and kind (yellow, reddish brown, or black) of melanin in the epidermis - skin exposure to sunlight stimulates melanocytes to produce more melanin pigment, resulting in tanning of the skin. - People who produce a lot of melanin have brown-toned skin, whereas people with less melanin are light skinned. 2. CAROTENE - the amount of carotene deposited in the stratum corneum and subcutaneous tissue - is an orange-yellow pigment plentiful in carrots and other orange, deep yellow, or leafy green vegetables - In people who eat large amounts of carotene -rich foods, the skin tends to take on a yellow-orange cast. 3. HEMOGLOBIN - the amount of oxygen-rich hemoglobin in the dermal blood vessels - In light-skinned people, the crimson color of oxygen-rich hemoglobin in the dermal blood supply flushes through the transparent cell layers above and gives the skin a rosy glow Emotions also influence skin color, and many alterations in skin color signal certain disease states: - 1. REDNESS, OR ERYTHEMA - may indicate embarrassment (blushing), fever, hypertension, inflammation, or allergy. - - 2. PALLOR, OR BLANCHING (PALE) - Under certain types of emotional stress (fear, anger, and others), some people become pale. - may also signify anemia, low blood pressure, or impaired blood flow into the area as these glands are formed by the cells of the stratum basale, they push into the deeper skin regions and ultimately reside almost entirely in the dermis. - they fall into two groups: sebaceous glands and sweat glands - 3. JAUNDICE OR A YELLOW CAST - an abnormal yellow skin tone usually signifies a liver disorder in which excess bile pigments accumulate in the blood, circulate throughout the body, and become deposited in body tissues 4. BRUISES - the black-and-blue marks of bruising reveal sites where blood has escaped from the circulation and has clotted in the tissue spaces. - Such clotted blood masses are called hematomas - an unusual tendency to bruise may signify a deficiency of vitamin C in the diet or hemophilia (bleeder’s disease) APPENDAGES OF THE SKIN - include cutaneous glands, hair and hair follicles, and nails - each of these appendages arises from the epidermis and plays a unique role in maintaining body homeostasis. 1. CUTAENOUS GLANDS - are all exocrine glands that release their secretions to the skin surface via ducts A. SEBACEOUS (OIL) GLANDS or oil glands are found all over the skin, except on the palms of the hands and the soles of the feet. their ducts usually empty into a hair follicle but some open directly onto the skin surface becomes very active when androgens (male sex hormones) are produced in increased amounts (in both sexes) during adolescence. Thus, the skin tends to become oilier during this period of life. *Sebum- product of the sebaceous glands - is a mixture of oily substances and fragmented cells - it is a lubricant that keeps the skin soft and moist and prevents the hair from becoming brittle - contains chemicals that kill bacteria, so it is important in preventing bacterial infection of the skin. - B. SWEAT GLANDS also called sudoriferous glands are widely distributed in the skin their number is staggering—more than 2.5 million per person. there are two types of sweat glands: 1. ECCRINE GLANDS are far more numerous and are found all over the body they produce sweat, vitamin C, traces of metabolic wastes (ammonia, urea, uric acid), and lactic acid (a chemical that accumulates during vigorous muscle activity) *sweat is acidic (pH from 4 to 6), a characteristic that inhibits the growth of certain bacteria, which are always present - - - on the skin surface. Typically, sweat reaches the skin surface via a duct that opens externally as a funnel-shaped sweat pore are an important and highly efficient part of the body’s heat-regulating equipment. They are supplied with nerve endings that cause them to secrete sweat when the external temperature or body temperature is too high 2. APOCRINE GLANDS are largely confined to the axillary (armpit) and genital areas of the body usually larger than eccrine glands, and their ducts empty into hair follicles their secretion contains fatty acids and proteins, as well as all the substances present in eccrine sweat; consequently, it may have a milky or yellowish color. The secretion is odorless, but when bacteria that live on the skin use its proteins and fats as a source of nutrients for their growth, it can take on a musky, sometimes unpleasant odor it begins to function during puberty under the influence of androgens. They play a minimal role in thermoregulation their precise function is not yet known, but they are activated by nerve fibers during pain and stress and during sexual arousal 2. HAIR AND HAIR FOLLICLES A. HAIR - millions of hairs, produced by hair follicles, are found all over the body surface except on the palms of the hands, soles of the feet, nipples, and lips - hairs are among the fastest growing tissues in the body - serves a few minor protective functions, such as guarding the head against bumps, shielding the eyes (via eyelashes), and helping to keep foreign particles out of the respiratory tract (via nose hairs) - may also help to attract sexual partners - - - - - hormones account for the development of hairy regions—the scalp and, in the adult, the pubic and axillary areas is a flexible epithelial structure Root = part of the hair enclosed in the hair follicle Shaft = the part projecting from the surface of the scalp or skin a hair forms by division of the well-nourished stratum basale epithelial cells in the matrix of the hair bulb at the deep end of the follicle Medulla = where each hair is made up of, is a central core consisting of large cells and air spaces, surrounded by a bulky cortex layer composed of several layers of flattened cells Cortex = enclosed by an outermost cuticle formed by a single layer of cells that overlap one another like shingles on a roof Cuticle = is the most heavily keratinized region; it provides strength and helps keep the inner hair layers tightly compacted. Because it is most subject to abrasion, the cuticle tends to wear away at the tip of the shaft, allowing the keratin fibrils in the inner hair regions to frizz out, a phenomenon called “split ends Hair pigment is made by melanocytes in the hair bulb, and varying amounts of different types of melanin combine to produce all varieties of hair color from pale blond to red to pitch black comes in a variety of sizes and shapes B. HAIR FOLLICLES are actually compound structures the inner epithelial root sheath is composed of epithelial tissue and forms the hair the outer fibrous sheath is actually dermal connective tissue. This dermal region supplies blood vessels to the epidermal portion and reinforces it Arrector pili = small bands of smooth muscle cells connect each side of the hair follicle to the dermal tissue 3. NAILS - a scalelike modification of the epidermis that corresponds to the hoof or claw of other animals - each nail has a free edge, a body, and a root Nail folds = folds of skin that overlapped the borders of the nail - Cuticle = the edge of the thick proximal nail fold - Nail Bed = beneath the nail where the stratum basale of the epidermis extends - Nail matrix = the thickened proximal area; is responsible for nail growth. As the matrix produces nail cells, they become heavily keratinized and die. are mostly nonliving material - are transparent and nearly colorless, but they look pink because of the rich blood supply in the underlying dermis. The exception to this is the region over the thickened nail matrix that appears as a white crescent and is called the lunule - when the supply of oxygen in the blood is low, the nail beds take on a cyanotic (blue) cast. HOMEOSTATIC IMBALANCES OF SKIN - skin can develop more than 1,000 different ailments most common skin disorder are infections with pathogens such as bacteria, viruses, or fungi Allergies = caused by abnormally strong immune responses; commonly seen in the skin Burns and skin cancers = less common but far more damaging to body well-being 1. INFECTIONS AND ALLERGIES A. ATHLETE’S FOOT - an itchy, red, peeling condition of the skin between the toes, resulting from an infection with the fungus Tinea pedis B. BOILS AND CARBUNCLES - Boils are caused by inflammation of hair follicles and surrounding tissues, commonly on - the dorsal neck Carbuncles are clusters of boils often caused by the bacterium Staphylococcus aureus C. COLD SORES (FEVER BLISTERS) - small fluid-filled blisters that itch and sting, caused by human herpesvirus 1 infection. The virus localizes in a cutaneous nerve, where it remains dormant until activated by emotional upset, fever, or UV radiation. It usually occur around the lips and in the oral mucosa of the mouth and nose D. CONTACT DERMATITIS - Itching, redness, and swelling of the skin, progressing to blistering It is caused by exposure of the skin to chemicals that provoke allergic responses in sensitive individuals E. IMPETIGO - pink, fluid-filled, raised lesions (commonly around the mouth and nose) that develop a yellow crust and eventually rupture caused by highly contagious staphylococcus or streptococcus infections F. PSORIASIS - characterized by reddened epidermal lesions covered with dry, silvery scales that itch, burn, crack, and sometimes bleed - a chronic condition; it is believed to be an autoimmune disorder in which the immune system attacks a person’s own tissues, leading to the rapid overproduction of skin cells. Attacks are often triggered by trauma, infection, hormonal changes, or stress. - when severe, psoriasis may be disfiguring 2. BURNS - is tissue damage and cell death caused by intense heat, electricity, UV radiation (sunburn), or certain chemicals (such as acids), which denature proteins and cause cell death in the affected areas - - - A. - when the skin is burned and its cells are destroyed, two life-threatening problems result: 1st = Without an intact boundary, the body loses its precious supply of fluids containing proteins and electrolytes as these seep from the burned surfaces nd 2 = Dehydration and electrolyte imbalance follow and can lead to a shutdown of the kidneys and circulatory shock to save the patient, lost fluids must be replaced immediately. The volume of fluid lost can be estimated indirectly by determining how much of the body surface is burned (extent of burns), using the rule of nines infection becomes the most important threat and is the leading cause of death in burn victims. Burned skin is sterile for about 24 hours. After that, pathogens easily invade areas where the skin has been destroyed and multiply rapidly in the nutrient-rich environment of dead tissues. The patient’s immune system becomes depressed within one to two days after severe burn injury burns are classified according to their severity (depth) as: FIRST-DEGREE (SUPERFICIAL) only the superficial epidermis is damaged the area becomes red and swollen It’s not usually serious and generally heal in two to three days Sunburn without blistering is a first-degree burn B. SECOND-DEGREE (SUPERFICIAL PARTIAL -THICKNESS BURNS) - involve injury to the epidermis and the superficial part of the dermis - the skin is red, painful, and blistered - because sufficient numbers of epithelial cells are still present, regrowth of the epithelium can Occur - ordinarily, no permanent scars result if care is taken to prevent infection. C. THIRD-DEGREE (FULL-THICKNESS BURNS) - often extend into the subcutaneous tissue, reflecting their categorization as full thickness burns - blisters are usually present, and the burned area appears blanched (gray-white) or blackened - because the nerve endings in the area are destroyed, the burned area is not painful - regeneration is not possible, and skin grafting must be done to cover the underlying exposed tissues. D. FOURTH-DEGREE (FULL-THICKNESS BURNS WITH DEEP-TISSUE INVOLVEMENT) - are also full-thickness burns, but they extend into deeper tissues such as bone, muscle, or tendons - these burns appear dry and leathery, and they require surgery and grafting to cover exposed tissue - in severe cases, amputation may be required to save the patient’s life CONSIDERED CRITICAL • Over 30 percent of the body has second-degree burns • Over 10 percent of the body has third- or fourth-degree burns • There are third- or fourth-degree burns of the face, hands, feet, or genitals • Burns affect the airway • Circumferential (around the body or limb) burns have occurred. - - Facial burns are particularly dangerous because of the possibility of burns in respiratory passageways, which can swell and cause suffocation Joint injuries are troublesome because the scar tissue that eventually forms can severely limit joint mobility Circumferential burns can restrict movement, and depending on location, can interfere with normal breathing 3. SKIN CANCER - numerous types of neoplasms (tumors) arise in the skin. Most are benign and do not spread (metastasize) to other body area - is the single most common type of cancer in humans - Frequent irritation of the skin by infections, chemicals, or physical trauma also seems to be a predisposing factor - three most common types of skin cancer: A. BASAL CELL CARCINOMA is the least malignant and most common skin cancer - Cells of the stratum basale, no longer honor the boundary between epidermis and dermis. They proliferate, invading the dermis and subcutaneous tissue - Cancerous lesions occur most often on sun -exposed areas of the face and often appear as shiny, dome-shaped nodules that later develop a central ulcer with a “pearly” beaded edge is relatively slow-growing, and metastasis seldom occurs before the lesion is noticed. When the lesion is removed surgically, 99 percent of cases are completely cured. B. SQUAMOUS CELL CARCINOMA - arises from the cells of the stratum spinosum - the lesions appear as scaly, reddened papules (small, rounded swellings) that gradually form shallow ulcers with firm, raised borders - appears most often on the scalp, ears, back of the hands, and lower lip, but can appear anywhere on the skin - it grows rapidly and metastasizes to adjacent lymph nodes if not removed - it is also believed to be induced by UV exposure. If it is caught early and removed surgically or by radiation therapy, the chance of complete cure is good C. MALIGNANT MELANOMA - is a cancer of melanocytes - It accounts for only about 5 percent of skin cancers, but it is often deadly - - can begin wherever there is pigment; most such cancers appear spontaneously, but some develop from pigmented moles It arises from accumulated DNA damage in a skin cell and usually appears as a spreading brown to black patch that metastasizes rapidly to surrounding lymph and blood vessels the chance for survival is about 50 percent, and early detection helps the American Cancer Society suggests that people who sunbathe frequently or attend tanning parlors examine their skin periodically for new moles or pigmented spots and apply the ABCDE rule for recognizing melanoma: (A) Asymmetry = Any two sides of the pigmented spot or mole do not match (B) Border irregularity = The borders of the lesion are not smooth but exhibit indentations (C) Color = The pigmented spot contains areas of different colors (black, brown, tan, and sometimes blue or red) (D) Diameter = The lesion is larger than 6 millimeters (mm) in diameter (the size of a pencil eraser) (E) Evolution = One or more of these characteristics (ABCD) is evolving, or changing - the usual therapy for malignant melanoma is wide surgical excision along with immunotherapy, a treatment that involves the patient’s immune system. Large lesions may also require radiation or chemotherapy after surgical removal REFERENCE: Essentials of Human Anatomy & Physiology 12th Edition. Marieb, E.N & Keller, 2016. S.M. Boston : Pearson. (PDF) NOTE: Some information were gathered online and others were from PDFs downloaded years ago D. LIGAMENTS fibrous cords that bind the bones together at joints FUNCTIONS OF BONES SKELETAL SYSTEM Skeleton = from Greek word meaning “dried-up body” includes bones, cartilages, joints, and ligaments the internal frame of the body (is beautifully formed and proportioned) strong yet light, perfectly adapted for its functions of protecting the body and allowing motion is essential for protecting organs, producing blood cells, storing essential minerals, and anchoring skeletal muscles so that their contractions cause body movements 2 SUBDIVISIONS OF SKELETON: joints give these parts of the skeleton flexibility and allow movement to occur. A. AXIAL SKELETON bones that form the longitudinal aspect of the body B. APPENDICULAR SKELETON bones of the limbs and girdles attached to axial skeleton COMPONENTS OF SKELETAL SYSTEM A. BONES contributes to body structure “steel girders” and “reinforced concrete” of the body adult skeleton is composed of 206 bones B. JOINTS sites where two or more bones meet and holds the bone together securely C. CARTILAGE reduce friction and model for bone formation A. SUPPORT form the internal framework and cradles soft organs of the body and cradles its soft organs. the bones of the legs act as pillars to support the body trunk when we stand the rib cage supports the thoracic wall B. PROTECTION bones protect soft body organs skull and vertebrae for brain and spinal cord rib cage for thoracic cavity organs C. ALLOW MOVEMENTS skeletal muscle, attached to bones by tendons (breath, walk, swim, throw a ball) D. STORAGE bone itself serves as a storehouse for minerals (Calcium and Phosphorus) Fat is stored the internal marrow cavities of bone E. BLOOD CELL FORMATION (HEMATOPOIESIS) occurs within the marrow cavities of certain bones TYPES OF BONE TISSUE A. COMPACT BONE dense, looks smooth and homogeneous B. SPONGY BONE - has spiky, open appearance like a sponge CLASSIFICATION OF BONES BASED ON SHAPES A. B. C. D. Long Short Flat Irregular C. FLAT BONES thin, flattened, and usually curved have two thin layers of compact bone surround a later of spongy bone Ex: Skull, ribs, and Sternum (breastbone) D. IRREGULAR BONES irregular shape mainly spongy bone with outer layer of compact bone Ex: Vertebrae and hip bones ANATOMY OF LONG BONE 1. DIAPHYSIS (SHAFT) makes up most of the bone’s lengths composed of compact bone is covered and protected by Periosteum =a fibrous connective tissue membrane Perforating fibers or Sharpeys fibers = hundreds of connective tissue fibers which secures the periosteum to the underlying bone A. LONG BONES typically longer than they are wide have shaft with enlarged ends contain mostly compact bones; spongy bone at the ends all of the bones of the limbs except the Patella (kneecap), wrist, and ankle bone Ex: Femur and Humerus B. SHORT BONES generally cube-shaped contain mostly spongy bone with an outer layer if compact bone includes bones of the wrist and ankle Sesamoid bones are a type of short bone which form within tendols (Patella) Ex: Carpals and Tarsals 2. EPIPHYSES ends of the bone each consists of a thin layer of compact bone enclosing an area filled of spongy bone Articular Cartilage = covers its external surface; glassy hyaline cartilage; it provides a smooth surface that decreases friction at the joint when covered by lubricating fluid Epiphyseal line = a thin line of bony tissue spanning the epiphysis that looks a bit different from the rest of the bone in that area; remnant of the Epiphyseal plate Epiphyseal plate = a flat plate of hyaline cartilage 3. MEDULLARY CAVITY cavity of the shaft on infants storage are for red marrow which produce blood cell formation in infants; which gradually replaced by yellow marrow Endosteum = a delicate connective tissue that covers the inner bony surface of the shaft 4. BONE MARKINGS surfaces are not smooth but scarred with bumps, holes and ridges sites of attachments for muscles, tendons, and ligaments passages for nerves and blood vessels two categories: A. PROJECTIONS OR PROCESSES grow out from the bone surface terms often begin with “T” B. DEPRESSIONS OR CAVITIES indentations in the bone terms often begin with “F” except facet MICROSCOPIC ANATOMY OF COMPACT BONE 1. OSTEON (HAVERSIAN SYSTEM) a unit of bone containing central canal and matrix rings 2. OSTEOCYTES found within the bone matrix in tiny cavities called Lacunae 3. CENTRAL (HAVERSIAN) CANAL opening in the center of an osteon carries blood vessels and nerves 4. LACUNAE cavities containing bone cells (Osteocytes) -arranged in concentric rings called Lamellae 5. LAMELLAE rings around the central canal sites of Lacunae 6. CANALICULI tiny canals - radiate from the central canal to lacunae form a transport system connecting all bone cells to a nutrient supply 7. PERFORATING CANALS (VOLKMANN’S CANALS) communication pathway from the outside of the bone to its interior run in the compact bone at right angles to the shaft (diaphysis) and central canals BONE FORMATION, GROWTH, AND REMODELING - Skeletons’ strongest and most supportive tissues  Cartilage  Bone In embryos, the skeleton is primarily made of hyaline cartilage. During development, much of this cartilage is replaced by bone Cartilage remains in isolated areas  Bridge of the nose  Parts of ribs  Joints BONE GROWTH (OSSIFICATION) also called as bone formation a process where most bones are develop using hyaline cartilage structures as their “models.” - Epiphyseal plates- allow for lengthwise growth of long bones during childhoof  New cartilage is continuously formed  Older cartilage becomes ossified  Cartilage is broken down  Enclosed cartilage is digested away, opening up a medullary cavity  Bone replaces cartilage through the action of Osteoblasts  Bones are remodeled and lengthened until growth stops  Bones are remodeled in response to two factors: 1. Blood calcium levels 2. Pull gravity and muscles on the skeleton  Bones grow in diameter/ width (called appositional growth) FRACTURE break in a bone two kinds:  CLOSED (SIMPLE) FRACTURE break that does not penetrate the skin  - OPEN (COMPOUND) FRACTURE broken bone penetrates through the skin COMMON TYPES OF FRACTURE TYPE OF BONE CELLS 1. OSTEOCYTES mature bone cells 2. OSTEOBLASTS bone-forming cells a bone-building cell which covered the hyaline cartilage model with bone matrix (a bone “collar”) 1. 2. 3. 4. 5. - Comminuted bone breaks into 3 or more fragments Compression bone is crushed Depressed broken bone portion is pressed inward Impacted broken bone ends are forced into each other Spiral ragged break occurs when excessive twisting forces are applied to a bone 6. Greenstick bone breaks incompletely 3. OSTEOCLASTS giant bone- destroying cells breaks down bone matrix for remodeling and release of calcium in response to parathyroid hormone BONE REMODELING is performed by both osteoblasts and osteoclasts is essential if bones are to retain normal proportions and strength during long-bone growth as the body increases in size and weight BONE FRACTURES bone fractures are treated by reduction and immobilization  CLOSED REDUCTION- the bone ends are coaxed back into their normal position by the physician’s hands  OPEN REDUCTION- surgery is performed, and the bone ends are secured together with pins or wires REPAIR OF BONE FRACTURES 1. Hematoma (blood-filled swelling) is formed 2. Break is splinted by fibrocartilage to form a callus 3. Fibrocartilage callus is replaced by a bony callus 4. Bony callus is remodeled to form a permanent patch AXIAL SKELETON forms the longitudinal axis of the body -divided into three parts:  Skull  Vertebral Column  Thoracic Cage SKULL formed by two sets of bones  Cranium- encloses and protects the fragile brain tissue  Facial bones- form a cradle for the eyes that is open to the anterior and allow the facial muscles to show our feelings through smiles and frowns Only the mandible is attached freely movable joint CRANIUM composed of eight large flat bones except for two sets of paired bones (the parietal and temporal), they are all single bones - FRONTAL BONE forms the forehead, the bony projections under the eyebrows, and the superior part of each eye’s orbit -  -  -  - -  - PARIETAL BONES the paired parietal bones form most of the superior and lateral walls of the cranium the sagittal suture is formed at the midline where the two parietal bones meet and the coronal suture is formed where the paired parietal bones meet the frontal bone TEMPORAL BONES lie inferior to the parietal bones and join them at the squamous sutures several important bone markings appear here  External acoustic meatus- a canal that leads to the eardrum and the middle ear. It is the route by which sound enters the ear.  Styloid process- a sharp, needlelike projection, is just inferior to the external auditory meatus. Many neck muscles use the styloid process as an attachment point  Zygomatic process- a thin bridge of bone that joins with the cheekbone (zygomatic bone) anteriorly  Mastoid process- full of air cavities (the mastoid sinuses), is a rough projection posterior and inferior to the external acoustic meatus. It provides an attachment site for some muscles of the neck. the mastoid sinuses are so close to the middle ear—a high-risk spot for infections— that they may become infected too, a condition called mastoiditis. It is so close to the brain that mastoiditis may spread to the brain.  Jugular foramen- at the junction of the occipital and temporal bones, allows passage of the jugular vein, the largest vein of the head, which drains blood from the brain OCCIPITAL BONE is the most posterior bone of the cranium It forms the base and back wall of the skull -  - -  - joins the parietal bones anteriorly at the lambdoid suture In the base is a large opening, the foramen magnum, which surrounds the lower part of the brain and allows the spinal cord to connect with the brain Lateral to the foramen magnum on each side are the rockerlike occipital condyles, which rest on the first vertebra of the spinal column SPHENOID BONE the butterfly-shaped sphenoid bone spans the width of the skull and forms part of the floor of the cranial cavity in the midline is a small depression, the sella turcica or Turk’s saddle, which forms a snug enclosure for the pituitary gland Foramen ovale, a large oval opening in line with the posterior end of the sella turcica allows fibers of cranial nerve V (the trigeminal nerve) to pass to the chewing muscles of the lower jaw (mandible) part of the eye orbits have two important openings  Optic canal- allows the optic nerve to pass to the eye,  Superior orbital fissure- through which the cranial nerves controlling eye movements (III, IV, and VI) pass Sphenoidal sinuses- the central part is riddled with air activities ETHMOID BONE is very irregularly shaped and lies anterior to the sphenoid It forms the roof of the nasal cavity and part of the medial walls of the orbits Crista Galli- Projecting from its superior surface; on each side of it are many small holes. These holey areas, the cribriform plates, allow nerve fibers carrying impulses from the olfactory (smell) receptors of the nose to reach the brain FACIAL BONES 14 bones make up the face 12 are paired; only the mandible and vomer are single  - MAXILLAE two maxillae or maxillary bones, fuse to form the upper jaw all facial bones except the mandible join the maxillae - maxillae carry the upper teeth in the alveolar process extensions of the maxillae called the palatine processes form the anterior part of the hard palate of the mouth maxillae contain sinuses, which drain into the nasal passages  PALATINE BONES lie posterior to the palatine processes of the maxillae forms the posterior part of the hard palate  - ZYGOMATIC BONES commonly referred to as the cheekbones form a good-sized portion of the lateral walls of the orbits  - LACRIMAL BONES are fingernail-sized bones forming part of the medial wall of each orbit each has a groove that serves as a passageway for tears  - the lower teeth lie in alveoli (sockets) in the alveolar process at the superior edge of the mandibular body ADDITIONAL:  - PARANASAL SINUSES hollow portions of bones surrounding the nasal cavity functions of paranasal sinuses 1. Ligthen the skull 2. Give resonance and amplification to voice NASAL BONES the small rectangular bones forming the bridge of the nose are the lower part of the skeleton of the nose is made up of hyaline cartilage  - VOMER BONE the single bone in the median line of the nasal cavity vomer forms the inferior part of the bony nasal septum, which separates the two nostrils  - INFERIOR NASAL CONCHAE are thin, curved bones projecting medially from the lateral walls of the nasal cavity  - MANDIBLE or lower jaw is the largest and strongest bone of the face it joins the temporal bones on each side of the face, forming the only freely movable joints in the skull the horizontal part of the mandible forms the chin. two upright bars of bone (the rami) extend from the body to connect the mandible with the temporal bone - - HYOID BONE serve as a moveable base for the tongue aids in swallowing and speech not really part of the skull it is the only bone of the body that does not articulate (form a joint) with any other bone it is suspended in the midneck region about 2 cm (1 inch) above the larynx (voicebox), where it is anchored by ligaments to the styloid processes of the temporal bones horseshoe-shaped, with a body and two pairs of horns - serves as a movable base for the tongue and as an attachment point for neck muscles that raise and lower the larynx when we swallow and speak THE FETAL SKULL large compare to the infant’s total body length Fetal skulls is 1/4 body length compared to adult skull which is 1/8 body length FONTANELS fibrous membranes connecting the cranial bones  Allow skull compression during birth  Allow the brain to grow during later pregnancy and infancy  Convert to bone within 24 months after birth THE VERTEBRAL COLUMN also known as Spine each vertebrae is given a name according to its location There are 24 single vertebral bones separated by intervertebral discs  seven cervical vertebrae are in the neck  twelve thoracic vertebrae are in chest region  five lumbar vertebrae are associated with the lower back extends from the skull, which it supports, to the pelvis, where it transmits the weight of the body to the lower limbs     Sacrum- formed in the fusion of 5 vertebrae Coccyx- formed in the fusion of 3-4 tiny irregular shaped vertebrae Primary curvatures- spinal curvatures of the thoracic and sacral regions -form a C- shaped curvature as in newborns Secondary curvatures- spinal curvatures of the cervical and lumbar regions -develop after birth -form an S- shaped curvature as in adults TYPICAL VERTEBRAE 1. BODY OR CERTRUM weight bearing part of the vertebra facing anteriorly in the vertebral column disclike 2. VERTEBRAL ARCH arch formed from the joining of all posterior extensions, the laminae and pedicles, from the vertebral body 3. VERTEBRAL FORAMEN canal through which the spinal cord passes. 4. TRANSVERSE PROCESSES two lateral projections from the vertebral arch. 5. SPINOUS PROCESS single projection arising from the posterior aspect of the vertebral arch 6. SUPERIOR AND INFERIOR ARTICULAR PROCESSES paired projections lateral to the vertebral foramen, allowing a vertebra to form joints with adjacent vertebrae REGIONS 1. CERVICAL VERTEBRAE seven cervical vertebrae (identified as C1 to C7) form the neck region of the spine Atlas and Axis - first two vertebrae; are different because they perform functions not shared by the other cervical vertebrae 2. THORACIC VERTEBRAE 12 thoracic vertebrae (T1 to T12) are all typical they are larger than the cervical vertebrae and are distinguished by the fact that they are the only vertebrae to articulate with the ribs. the body is somewhat heart-shaped and has two costal facets (articulating surfaces) on each side, which receive the heads of the ribs transverse processes of each thoracic vertebra articulate with the knoblike tubercles of the ribs the spinous process is long and hooks sharply downward, causing the vertebra to look like a giraffe’s head viewed from the side 3. LUMBAR VERTEBRAE five lumbar vertebrae (L1 to L5) have massive, blocklike bodies that are somewhat kidney bean–shaped their short, hatchet-shaped spinous processes make them look like a moose head from the lateral aspect because most of the stress on the vertebral column occurs in the lumbar region, these are the sturdiest of the vertebrae 4. SACRUM is formed by the fusion of five vertebrae - it articulates with L5, and inferiorly it connects with the coccyx forms the posterior wall of the pelvis its posterior midline surface is roughened by the median sacral crest, the fused spinous processes of the sacral vertebrae blood-forming (hematopoietic) tissue for the diagnosis of suspected blood diseases - 5. COCCYX is formed from the fusion of three to five tiny, irregularly shaped vertebrae it is the human “tailbone,” a remnant of the tail that other vertebrate animals have - BONY THORAX forms a cage to protect major organs routinely called the thoracic cage because it forms a protective cage of slender bones and cartilages around the organs of the thoracic cavity (heart, lungs, and major blood vessels). consists of three parts: - - 1. STERNUM (BREASTBONE) flat bone the result of the fusion of three bones—the manubrium, body, and xiphoid process it is attached directly to the first seven pairs of ribs via costal cartilages has three important bony landmarks:  - JUGULAR NOTCH can be palpated easily it is at the level of the third thoracic vertebra  - STERNAL ANGLE results where the manubrium and body meet at a slight angle to each other, so that a transverse ridge is formed at the level of the second ribs It provides a handy reference point for counting ribs to locate the second intercostal space for listening to certain heart valves -  - - XIPHISTERNAL JOINT the point where the sternal body and xiphoid process fuse, lies at the level of the ninth thoracic vertebra because the sternum is so close to the body surface, it is easy to obtain samples from it of - - 2. RIBS True ribs (pairs 1-7); attach directly to the sternum by costal cartilages False ribs (pairs 8-12) the next five pairs ,either attach indirectly to the sternum or are not attached to the sternum at all Floating ribs (pairs 11-12); lack the sternal attachments twelve pairs of ribs form the walls of the bony Thorax all the ribs articulate with the vertebral column posteriorly and then curve downward and toward the anterior body surface Intercostal spaces- spaces between the ribs; are filled with the intercostal muscles, which aid in breathing 3. THORACIC VERTEBRAE APPENDICULAR SKELETON composed of 126 bones 1. PECTORAL (SHOULDER) GIRDLE composed of two bones: a. CLAVICLE collarbone slender, doubly curved bones articulates with the ternum medially and with the scapula laterally b. SCAPULA or as shoulder blade commonly called as “wings” articulates with the clavicle at the acromioclavicular joint articulates with the arm bone at the glenoid cavity - these bones allow the upper limb to have exceptionally free movement BONES OF THE UPPER LIMBS 1. ARM A. HUMERUS forms the arm single bone proximal end articulation (head articulates with the glenoid cavity of the scapula) distal end articulation (trochlea and capiulum articulate with the bones of the forearm) B. FOREARM has two bones:  Ulna- medial bone in anatomical position - proximal end articulation (coronoid process and olecranon articulate with the humerus)  Radius- lateral bone in anatomical position proximal end articulation (head articulates with the capitulum of the humerus) C. HAND  Carpals- forms the wrist 8 bones arranged in two irregular rows of four bones in each hand are bound together by ligaments that restrict movements between them  Metacarpals- palm are numbered 1 to 5 from the thumb side of the hand toward the little finger when the fist is clenched, the heads of the metacarpals become obvious as the “knuckles”  Phalanges- bones of fingers and thumb 14 phalanges in each hand in each finger, there are 3 bones in each thumb, there are 2 bones 3. Part of the large intestine - bony pelvis is divided into two regions: 1. FALSE PELVIS is superior to the true pelvis it is the area medial to the flaring portions of the ilia 2. TRUE PELVIS is surrounded by bone and lies inferior to the flaring parts of the ilia and the pelvic brim BONES OF PELVIC GIRDLE formed by two coxal (ossa coxae) bones, commonly called hip bones, and the sacrum Pelvis = Coccyx + pelvic girdle the total weight of the upper body rests on the pelvis composed of three pairs of fused bones: 1. ILIUM which connects posteriorly with the sacrum at the sacroiliac joint a large, flaring bone that forms most of the hip bone when you put your hands on your hips, they are resting over the alae, or winglike portions, of the ilia Iliac crest = is an important anatomical landmark 2. ISCHIUM is the “sit-down bone,” so called because it forms the most inferior part of the coxal bone 3. PUBIS is the most anterior and inferior part of a coxal bone - it protects several organs: 1. Reproductive system 2. Urinary bladder GENDER DIFFERENCES OF THE PELVIS 1. The female inlet is larger and more circular 2. The female pelvis as a whole is shallower, and the bones are lighter and thinner 3. The female ilia flare more laterally 4. The female sacrum is shorter and less curved 5. The female ischial spines are shorter and farther apart, thus the outlet is larger 6. The female pubic arch is more rounded because the angle of the pubic arch is greater BONES OF THE LOWER LIMBS carry our total body weight when we are erect three segments: 1. FEMUR or thigh bone; the only bone in the thigh heaviest, strongest bone in the body proximal end articulation (head articulates with the acetabulum of the coxal (hip) bone) distal end articulation (lateral and medial condyles articulate with the tibia in the lower leg) 3. FOOT supports our body weight and serves as a lever that allows us to propel our bodies forward when we walk run composed of: 1. TARSALS forms the posterior half of foot composed of 7 tarsal bones Calcaneus (heel bone) and Talus = two largest tarsals which carries our body weight the most 2. METATARSALS 5 bones form the sole of the foot 3. PHALANGES 14 bones which form the toes each toe has three phalanges, except the great toe, which has two 2. LEG connected along their length by an interosseous membrane has two bones: 1. TIBIA or shinbone larger and medially oriented proximal end articulation (medial and lateral condyles articulate with the femur to form the knee joint) 2. FIBULA thin and sticklike, lateral to the tibia has no role in forming the knee joint ARCHES OF THE FOOT -bones of the foot are arranged to form three strong arches: 1. Two longitudinal 2. One transverse   Ligaments - which bind the foot bones together Tendons - of the foot muscles help to hold the bones firmly in the arched position but still allow a certain amount of give, or springiness JOINTS also called articulations with one exception (the hyoid bone of the neck), every bone in the body forms a joint with at least one other bone hold bones together allow for mobility two ways to classify: 1. FUNCTIONALLY focuses on the amount of movement the joint allow at 2. STRUCTURALLY there are fibrous, cartilaginous, and synovial joints are based on whether fibrous tissue, cartilage, or a joint cavity separates the bony regions the joint STRCUTURAL CLASSIFICATION OF JOINTS 1. FIBROUS JOINTS generally immovable bones united by collagenic fibers types: a. SUTURES immobile  Syndesmoses - allows more movement than sutures but still immobile ex: Distal end of tibia nad fibula  Gomphosis- immobile 2. CARTILAGINOUS JOINTS immovable or slightly moveable bones connected by cartilage types: a. SYNCHONDROSES (SYNARTHROTIC) immovable joints (ex: bones on ribs 1-7 and sternum) b. SYMPHYSES (AMPHIARTHROTIC) slightly movable ex: pubic symphysis, intervertebral joints c. JOINT CAVITY is filled with synovial fluid d. REINFORCING LIGAMENTS the fibrous layer of the capsule is usually reinforced with ligaments 3. SYNOVIAL JOINTS freely moveable articulating bones are separated by a joint cavity synovial fluid is found in the joint cavity features: a. ARTICULAR CARTILAGE (HYALINE CARTILAGE) covers the ends of bones b. ARTICULAR CAPSULE encloses joint surfaces and lined with synovial membrane TYPES OF SYNOVIAL JOINTS BASED ON SHAPES STRUCTURES ASSOCIATED WITH THE SYNOVIAL JOINT 1. BURSAE flattened fibrous sacs  Lined with synovial membranes  Filled with synovial fluid  Not strictly part of the synovial joint but often found closely associated 2. TENDON SHEATH elongated bursa that wraps around a tendon INFALAMMATORY CONDITIONS ASSOCIATED WITH JOINTS 1. BURSITIS inflammation of a bursa usually caused by a blow or friction 2. SPRAIN ligaments or tendons are damaged 3. ARTHRITIS inflammatory or degenerative disease of joints over 100 different types most widespread crippling disease in the US Initial symptoms: pain, stiffness, swelling of the joint - shapes of the articulating bone surfaces determine what movements are allowed at a joint 1. PLANE JOINT the articular surfaces are essentially flat, and only short slipping or gliding movements are allowed movements are nonaxial (gliding back and forth does not involve rotation around any axis ex: intercarpal joints of the wrist 2. HINGE JOINT the cylindrical end of one bone fits into a trough-shaped surface on another bone angular movement is allowed in just one plane ex: elbow joint, ankle joint, and the joints between the phalanges of the fingers classified as uniaxial ( movement around one axis only) 3. PIVOT JOINT the rounded end of one bone fits into a sleeve or ring of bone (and possibly ligaments classified as uniaxial 4. CONDYLAR JOINT “knucklelike” the eggshaped articular surface of one bone fits into an oval concavity in another both of these articular surfaces are oval - movement occurs around two axes; hence, these joints are biaxial as in knuckle (metacarpophalangeal) joints 5. SADDLE JOINTS each articular surface has both convex and concave areas, like a saddle for a horse biaxial joints ex: carpometacarpal joints in the thumb, which are responsible for our opposable thumbs 6. BALL-AND-SOCKET JOINT the spherical head of one bone fits into the round socket in another multiaxial joints allow movement in all axes, including rotation,and are the most freely moving synovial joints ex: shoulder and hip REFERENCE: Essentials of Human Anatomy, 12th Edition. Marieb, E.N. & K. S.M., 2016. Pearson, NY. (PDF) NOTE: Some information were gathered online and others were from PDFs downloaded years ago COMPARISON OF SKELETAL, CARDIAC, AND SMOOTH CHARACTERISTICS SKELETAL CARDIAC SMOOTH Body location Attached to bone or skin (for some facial muscles) Walls of the heart Mostly in walls of visceral organs (other than the heart) Cell shape and appearance Single, very long, cylindrical multinucleate cells with very obvious striations Branching chains of cells, uninucleate, strations, intercalated discs Single, fusiform, uninucleate, no striations Connective tissue components Endomysium, Perimysium, and Epimysium Endomysium Endomysium Regulation of contraction Voluntary Involuntary Involuntary Speed of contraction Slow to fast Slow Very slow Rhythmic contractions No Yes Yes, in some MUSCULAR SYSTEM FUNCTIONS: 1. Responsible for body movement 2. Maintain posture 3. Respiration 4. Production of body heat 5. Communication 6. Heartbeat 7. Contraction of organs and vessels 8. Muscles are responsible for all types of body movement 3 TYPES: 1. Skeletal 2. Cardiac 3. Smooth SIMILARITIES OF THESE 3 TYPES: - Skeletal and smooth muscle cells are elongated (muscle cell = muscle fiber) - the ability of muscle to shorten, or contract, depends on two types of myofilaments, the muscle cell equivalents of the microfilaments of the cytoskeleton - share some terminology  Prefixes myo- and mys refer to “muscle”  Prefix sarco- refers to “flesh” 1. SKELETAL MUSCLE - Muscle fibers, which are large, cigar-shaped, multinucleate cell, are packed into organs that attach to the skeleton - most are attached by tendons to bones - also known as: -  Striated— its fibers have obvious stripe/ have visible banding  Voluntary—subject to conscious control can be activated by reflexes (without our “willed command covers our bone and cartilage framework helps form the smooth contours of the body its tissue can contract rapidly and with great force, but it tires easily and must rest after short periods of activity its fibers are soft and fragile produce movement maintain Posture and Body Position Generate Heat CONNECTIVE TISSUE WRAPPINGS OF SKELETAL MUSCLE - Cells are surrounded and bundled by connective tissue: 1. ENDOMYSIUM - encloses a single muscle fiber 2. PERIMYSIUM - wraps around a several sheathed muscle fibers 3. EPIMYSIUM - covers the entire skeletal muscle SKELETAL MUSCLE ATTACHMENTS - the ends of Epimysium blends into a connective tissue attachment 1. TENDONS - cord-like structures - provides durability and conserving space - are mostly tough collagen fibers 2. APONEUROSES - sheet-like structures - Attach muscles indirectly to bones, cartilages, or connective tissue covering SKELETAL MUSCLE ATTACHMENTS - Sites of muscle attachment 1. Bones 2. Cartilages 3. Connective tissue coverings 2. SMOOTH MUSCLE - no striations - Involuntary—no conscious control - found mainly in the walls of hollow organs - fibers are spindle-shaped cells, uninucleate, and surrounded by scant endomysium - fibers are arranged in layers, and most often there are two such layers, one running circularly and the other longitudinally - contraction is slow and sustained 3. CARDIAC MUSCLE - Found only in the walls of the heart - striated, uninucleate, and involuntary - cardiac cells are cushioned by small amounts of endomysium and are arranged in spiral or figure 8–shaped bundles - fibers are branching cells joined by special gap junctions called intercalated discs - usually contracts at a fairly steady rate set by the heart’s “in-house” pacemaker MICROSCOPIC ANATOMY OF SKELETAL MUSCLE SARCOLEMMA - A specialized plasma membrane where many oval nuclei can be seen beneathe it MYOFIBRILS - long ribbonlike organelles inside muscle cell - pushes nuclei aside - are aligned to give distinct bands  I band = light band - Contains only thin filaments  A band = dark band - Contains the entire length of the thick filaments CONTRACTILITY - ability to forcibly shorten when an adequate stimulated SARCOMERE - contractile unit of a muscle fiber EXTENSIBILITY - ability of muscle cells to be stretched MYOFILAMENTS - two types: ELASTICITY - ability to recoil and resume resting length after being stretched 1. THICK FILAMENTS - made mostly of bundled molecules of myosin filaments - has ATPase enzymes - have heads (extensions, or cross bridges) - Myosin and actin overlap somewhat 2. - THIN FILAMENTS composed of actin filaments anchored to the Z disc at rest, within the A band there is a zone that lacks actin filaments - called either the H zone or bare zone SARCOPLASMIC RETICULUM - specialized smooth endoplasmic reticulum - stores and releases calcium - surrounds the myofibril SKELETAL MUSCLE ACTIVITY STIMULATION AND CONTRACTION OF SINGLE SKELETAL MUSCLE CELLS IRRITABILITY - responsiveness; the ability to receive and respond to a stimulus NERVE STIMULUS AND ACTION POTENTIAL - Skeletal muscle fibers must be stimulated by a motor neuron (nerve cell) to contract - Motor unit—one motor neuron and all the skeletal muscle cells stimulated by that neuron - Neuromuscular junction - association site of axon terminal of the motor neuron and muscle - Synaptic cleft - gap between nerve and muscle - area between nerve and muscle is filled with interstitial fluid - action potential reaches the axon terminal of the motor neuron - Calcium channels open and calcium ions enter the axon terminal TRANSMISSION OF NERVE IMPULSE TO MUSCLE - Calcium ion entry causes some synaptic vesicles to release their content (acetylcholine, a neurotransmitter) by exocytosis - Neurotransmitter—chemical released by nerve upon arrival of nerve impulse in the axon terminal - neurotransmitter for skeletal muscle is acetylcholine (ACh) - Acetylcholine attaches to receptors on the sarcolemma of the muscle cell - In response to the binding of ACh to a receptor, the sarcolemma becomes permeable to sodium (Na+) Sodium rushes into the cell generating an action potential and potassium leaves the cell Once started, muscle contraction cannot be stopped - - THE SLIDING FILAMENT THEORY OF MUSCLE CONTRACTION - Activation by nerve causes myosin heads (cross bridges) to attach to binding sites on the thin filament Myosin heads then bind to the next site of the thin filament and pull them toward the center of the sarcomere This continued action causes a sliding of the myosin along the actin The result is that the muscle is shortened (contracted) CONTRACTION OF SKELETAL MUSCLE GRADED RESPONSES - different degrees of shortening, which generate different amounts of force - can be produced in two ways:  Changing the he frequency of muscle stimulation  Changing the number of muscle cells being stimulated at one time - types of graded responses 1. MUSCLE RESPONSE TO INCREASINGLY RAPID STIMULATION - Muscle twitches = Single, brief contraction - sometimes result from certain nervous system problems - not a normal muscle function - - Summing of contractions = one contraction is immediately followed by another - the muscle does not completely return to a resting state due to more frequent stimulations - the effects are added Unfused (incomplete) tetanus - some relaxation occurs between contractions but nerve stimuli arrive at an even faster rate than during summing of contractions - Unless the muscle contraction is smooth and sustained, it is said to be in unfused tetanus Fused (complete) tetanus - no evidence of relaxation before the following contractions - Frequency of stimulations does not allow for relaxation between contractions the result is a smooth and sustained muscle contraction 2. MUSCLE RESPONSE TO STRONG STIMULI - Muscle force depends upon the number of fibers stimulated - More fibers contracting results in greater muscle tension - Muscles can continue to contract unless they run out of energy TYPES OF MUSCLE CONTRACTIONS 1. ISOTONIC CONTRACTIONS - Myofilaments are able to slide past each other during contractions - The muscle shortens and movement occurs - Example: bending the knee; rotating the arm 2. ISOMETRIC CONTRACTIONS - contraction in which the muscles do not shorten - Tension in the muscles increases - Example: push against a wall with bent elbows MUSCLE TONE - some of the fibers are contracted even in a relaxed muscle - Different fibers contract at different times to provide muscle tone and to be constantly ready EFFECT OF EXERCISE ON MUSCLES - it increases muscle size, strength, and endurance 1. AEROBIC/ ENDURANCE EXERCISE - results in stronger, more flexible muscles with greater resistance to fatigue - makes body metabolism more efficient - Improves digestion, coordination - helps us reach a steady rate of ATP production and improves the efficiency of aerobic respiration TYPES OF BODY MOVEMENTS 1. - 2. RESISTANCE/ ISOMETRIC EXERCISE - increases muscle size and strength 2. - MUSCLES AND BODY MOVEMENTS - Movement is attained due to a muscle moving an attached bone - Muscles are attached to at least two points - 1. ORIGIN - attachment to the immovable or less movable bone 2. INSERTION - attachment to an movable bone. When the muscle contracts, the insertion moves toward the origin FLEXION Decreases the angle of the joint Brings two bones closer together Typical of bending hinge joints or ball-and-socket joints EXTENSION Opposite of flexion movement that increases the angle or distance between two bones or parts of the body Typical of straightening the elbow or knee Extension beyond 180° is hypertension 3. ROTATION - Movement of a bone around its longitudinal axis - Common in ball-and-socket joints - Ex: when you move atlas around the dens of axis (shake your head “no”) 4. ABDUCTION - movement of a limb away from the midline of the body 5. ADDUCTION - Opposite of abduction - Movement of a limb toward the midline 6. CIRCUMDUCTION - Combination of flexion, extension, abduction, and adduction - Commonly seen n in ball-and-socket joints INTERACTIONS OF SKELETAL MUSCLES IN THE BODY (TYPES OF MUSCLES) 1. PRIME MOVER - muscle that has the major responsibility for a certain movement (agonist) SPECIAL MOVEMENT 1. DORSIFLEXION - Lifting the foot so that the superior surface approaches the shin (toward the dorsum) - corresponds to extension and hyperextension of the hand at the wrist 2. - PLANTAR FLEXION pointing the toes away from your head “Planting” the foot toward the sole corresponds to flexion of the hand 3. INVERSION - Turn sole of foot medially 4. EVERSION - Turn sole of foot laterally 5. SUPINATION - forearm rotates laterally so palm faces anteriorly - Radius and ulna are parallel 6. PRONATION - Forearm rotates medially so palm faces posteriorly - Radius and ulna cross each other like an X 7. OPPOSITION - Move thumb to touch the tips of other fingers on the same hand 2. ANTAGONIST - muscle that opposes or reverses a prime move - can be prime movers in their own right 3. SYNERGISTS - help prime movers by producing the same movement or by reducing undesirable movements 4. FIXATOR - specialized synerigists - stabilizes the origin of a prime mover NAMING SKELETAL MUSCLES 1. BY DIRECTION OF MUSCLE FIBERS - Example: Rectus (straight) - When a muscle’s name includes the term rectus (straight), its fibers run parallel to that imaginary line 2. BY RELATIVE SIZE OF THE MUSCLE - Such terms as maximus (largest), minimus (smallest), and longus (long) 3. BY LOCATION OF THE MUSCLE - Example: Temporalis (temporal bone) 4. BY NUMBER OF ORIGINS - Example:the biceps muscle of the arm has two heads, or origins, and the triceps muscle has three 5. BY LOCATION OF THE MUSCLE’S ORIGIN AND INSERTION - Example: Sterno (on the sternum) clavicle (cleido) and inserts on the mastoid process of the temporal bone 6. BY SHAPE OF THE MUSCLE - Example: Deltoid (triangular) CHEWING MUSCLES 1. MASSETER - covers the angle of the lower jaw - closes the jaw and elevates mandible 7. BY ACTION OF THE MUSCLE - Example: Flexor and extensor (flexes or extends a bone) 2. TEMPORALIS - fan-shaped muscle overlying the temporal bone - It inserts into the mandible - synergist of the masseter, closes jaw GROSS ANATOMY OF SKELETAL MUSCLES NECK MUSCLES HEAD AND NECK MUSCLES 1. PLATYSMA - a single sheetlike muscle that covers the anterolateral neck - pulls the corners of the mouth inferiorly FACIAL MUSCLES 1. FRONTALIS - covers the frontal bone - raises eyebrows and wrinkle your forehead 2. ORBICULARIS OCULI - run in circles around the eyes - closes eyes, squints, blinks, winks 3. - ORBICULARIS ORIS the circular muscle of the lips Often called the “kissing” muscle closes mouth and protrudes the lips 4. BUCCINATOR - muscle runs horizontally across the cheek and inserts into the orbicularis oris - flattens the cheek, chews 5. ZYGOMATICUS - extends from the corner of the mouth to the cheekbone - raises corners of the mouth 2. STERNOCLEIDOMASTOID - two-headed muscles, one found on each side of the neck - of the two heads of each muscle, one arises from the sternum, and the other arises from the clavicle - flexes the neck, rotates the head MUSCLES OF TRUNK, SHOULDER, ARM ANTERIOR MUSCLES 1. PECTORALIS MAJOR - major is a large fan-shaped muscle covering the upper part of the chest. - adducts and flexes the humerus INTERCOSTAL MUSCLES 1. EXTERNAL INTERCOSTALS - raise rib cage during inhalation 2. INTERNAL INTERCOSTALS - depress the rib cage to move air out of the lungs when you exhale forcibly MUSCLES OF THE ABDOMINAL GIRDLE 1. RECTUS ABDOMINIS - paired straplike rectus abdominis muscles - flexes vertebral column and compresses abdominal contents (defecation, childbirth, forced breathing) 2. EXTERNAL OBLIQUE - paired superficial muscles that make up the lateral walls of the abdomen - flex vertebral column; rotate trunk and bend it laterally 3. INTERNAL OBLIQUE - paired muscles deep to the external obliques - flex vertebral column; rotate trunk and bend it laterally 4. TRANSVERSUS ABDOMINIS - the deepest muscle of the abdominal wall - compresses abdominal contents POSTERIOR MUSCLES 1. TRAPEZIUS - the most superficial muscles of the posterior neck and upper trunk - elevates, depresses, adducts, and stabilizes the scapula 2. LATISSIMUS DORSI - two large, flat muscles that cover the lower back - extends and adducts the humerus 3. ERECTOR SPINAE - Each erector spinae is a composite muscle consisting of three muscle columns (longissimus, iliocostalis, and spinalis) that collectively span the entire length of the vertebral column - back extension 4. QUADRATUS LUMBORUM - form part of the posterior abdominal wall - flexes the spine laterally 5. DELTOID - fleshy, triangle-shaped muscles that form the rounded shape of your shoulders - arm abduction - Muscles that arise from the shoulder girdle and cross the shoulder joint to insert into the humerus include:  Pectoralis major  Latissimus dorsi  Deltoid MUSCLES OF THE UPPER LIMB 1. BICEPS BRACHII - the most familiar muscle of the arm because it bulges when you flex your elbow - supinates forearm, flexes elbow 2. BRACHIALIS - lies deep to the biceps brachii and, like the biceps, is a prime mover in elbow flexion - lifts the ulna as the biceps lifts the radius 3. BRACHIORADIALIS - a fairly weak muscle that arises on the humerus and inserts into the distal forearm - it resides mainly in the forearm 4. TRICEPS BRACHII - the only muscle fleshing out the posterior humerus - elbow extension (antagonist to biceps brachii) - straightens the arm—for instance, to deliver a strong jab in boxing Muscles of the forearm, which insert on the hand bones and cause their movement include: 1. FLEXOR CARPI - wrist flexion 2. FLEXOR DIGITORUM - finger flexion 3. EXTENSOR CARPI - wrist extension 4. EXTENSOR DIGITORUM - finger extension MUSCLES OF THE LOWER LIMB Muscles causing movement at the hip joint include: 1. GLUTEUS MAXIMUS - superficial muscle of the hip that forms most of the flesh of the buttock - It is a powerful hip extensor that acts to bring the thigh in a straight line with the pelvis - hip extension 2. GLUTEUS MEDIUS - runs from the ilium to the femur, beneath the gluteus maximus for most of its length - hip abduction, steadies pelvis when walking 3. ILIOPSOAS - a fused muscle composed of two muscles, the iliacus and the psoas major - hip flexion, keeps the upper body from falling backward when standing erect 4. ADDUCTOR MUSCLES - forms the muscle mass at the medial side of each thigh - adduct the thighs Muscles causing movement at the knee joint: 1. HAMSTRING GROUP - muscles forming the muscle mass of the posterior thigh - thigh extension and knee flexion - consists of three muscles:  biceps femoris  Semimembranosus  Semitendinosus which originate on the ischial tuberosity and run down the thigh to insert on both sides of the proximal tibia 2. SARTORIUS - . It runs obliquely across the thigh from the anterior iliac crest to the medial side of the tibia - It is a weak thigh flexor commonly referred to as the “tailor’s” muscle because it acts as a synergist to help tailors sit with both legs crossed in front of them 3. QUADRICEPS GROUP - group consists of four muscles:  rectus femoris  three vastus muscles that flesh out the anterior thigh - extends the knee Muscles causing movement at ankle and foot: REFERENCE: 1. TIBIALIS ANTERIOR - a superficial muscle on the anterior leg - It arises from the upper tibia and then parallels the anterior crest as - it runs to the tarsal bones, where it inserts by a long tendon - dorsiflexion, foot inversion Essentials of Human Anatomy & Physiology 12th Edition. Marieb, E.N & Keller, 2016. S.M. Boston : Pearson. (PDF) 2. EXTENSOR DIGITORUM LONGUS - arises from the lateral tibial condyle and proximal three-quarters of the fibula and inserts into the phalanges of toes 2 to 5 - toe extension and dorsiflexion of the foot 3. FIBULARIS MUSCLES - The three fibularis muscle:  Longus  Brevis  Tertius are found on the lateral part of the leg - They arise from the fibula and insert into the metatarsal bones of the foot - plantar flexion, foot eversion 4. GASTROCNEMIUS - a two-bellied muscle that forms the curved calf of the posterior leg a prime mover for plantar flexion of the foot often called the “toe dancer’s” muscle. 5. - SOLEUS Deep to the gastrocnemius it does not affect knee movement it inserts into the calcaneal tendon plantar flexion NERVOUS SYSTEM - provides for higher mental function and emotional expression maintains homeostasis regulates the activities of muscles and glands communication by this involves a combination of electrical and chemical signals all body systems are under control or regulation of this system works with endocrine system in maintaining homeostasis and regulating systems has three overlapping functions: 1. It uses millions of sensory receptors to monitor changes occurring both inside and outside the body  Stimuli = the changes  Sensory input = gathered information 2. It processes and interprets the sensory input and decide what should be done at each moment = Integration 3. It then causes a response or effect by activating muscles or glands via Motor Input ORGANIZATION OF THE NERVOUS SYSTEM STRUCTURAL CLASSIFICATION - has two subdivisions: 1. - CENTRAL NERVOUS SYSTEM (CNS) consists of the brain and spinal occupies the dorsal body cavity act as the integrating and command centers of nervous system - interprets incoming sensory information - issues instructions based on past experience and current conditions 2. PERIPHERAL NERVOUS SYSTEM (PNS) - includes all parts of nervous system outside the CNS (nerves that extend from spinal cord and brain)  Spinal nerves - carry impulses to and from the spinal cord  Cranial nerves - carry impulses to and from the brain - both serve as communication lines PNS FUNCTIONAL CLASSIFICATION - divides into two principal subdivisions: 1. SENSORY/ AFFERENT DIVISION - consists of nerves that convey carries impulses to the CNS from sensory receptors - keeps the CNS constantly informed of events going inside and outside the body  Somatic Sensory Fibers - delivers impulses from the skin, skeletal muscles, and joints  Visceral Sensory Fibers - transmit impulses from the visceral organs 2. MOTOR/ EFFERENT DIVISION - carries impulses from CNS to effector organs (muscles and glands) - impulses causes a motor response - has two subdivisions:  Somatic/ Voluntary Nervous System - allows us to voluntarily control our skeletal muscles - not all skeletal muscle activity controlled by this is voluntary  Autonomic/ Involuntary Nervous System - regulates events that are involuntary - has two parts:  Sympathetic  Parasympathetic - what one stimulates, the other inhibits NERVOUS TISSUE: STRUCTURE AND FUNCTION - has two principal types of cells 1. SUPPORTING CELLS - has two major varieties:  Schwann Cells - form the myelin sheathes around nerve fibers in the PNS  Satellite Cells - act as protective, cushioning cells for peripheral neuron cell bodies NEUROGLIA - also called as glial cells or glia - supporting cells in CNS that are “lumped together” - not able to transmit nerve impulses - include many types of cells:  Astrocytes - abundant star -shaped cells that account for nearly half of neural tissue - form a living barrier between capillaries and neurons - help determine capillary permeability - play a role in making exchanges between capillaries and neurons - helps control the chemical environment in the brain  Microglia spinderlike phagocytes that monitor the health of nearby neurons dispose of debris  Ependymal cells - lines the central cavities of the brain and spinal cord  Oligodendrocytes - wraps their flat extensions tightly around the nerve fibers, producing fatty insulating coverings called Myelin Sheaths 2. NEURONS - also called as nerve cells - highly specialized to transmit message/ nerve impulses from one part of the body to another - differ structurally from one another but all have cell body  Cell body - the metabolic center of the neuron - cytoplasm surrounding the nucleus contains the usual organelles, except that it lacks centrioles - abundant in cell body:  Nissl Bodies - rough ER  Neurofibrils - intermediate filaments that are important in maintaining cell shape  Processes - armlike fibers very in length  Dendrites - conveys incoming messages toward the cell body  Axons - generates nerve impulses and conduct them away from the cell body  Axon Hillock - conelike region of the cell body where axon arises  Axon terminals - contains hundreds of tiny vesicles, or membranous sacs, that contain chemicals called neurotransmitters  Synaptic cleft - a tiny gap which separates each axon terminal from the next neuron  Synapse - a functional junction where an impulse is transmitted from one neuron to another  Myelin Sheaths - a whitish, fatty material which has a waxy appearance, covers most of the long fibers - protects and insulates the fibers - increases the transmission rate of nerve impulses  Terminology - Nuclei - clusters in CNS where cell bodies are found - Ganglia - small collections of cell bodies that are found in a few sites outside the CNS in the PNS - Tracts - bundles of nerve fibers running through the CNS - Nerves - bundles of nerve fibers running through the PNS  Functional Classification - - Sensory/ Afferent neurons - neurons carrying impulses from sensory receptors to the CNS Cutaneous Sense Organs - simpler types of sensory receptors in the skin Proprioceptors - simpler types of sensory receptors in the muscles and tendons that detects the amount of stretch or tension in skeletal muscles Motor/ Efferent neurons - neurons carrying impulses from the CNS to the viscera and/or muscles and glands Interneurons/ Association neurons connects the motor and sensory neurons in neural pathways - -  Cerebral Cortex - speech, memory, logical and emotional responses, consciousness, the interpretation of sensation, and voluntary movement  Cerebral White Matter - most of the remaining cerebral hemisphere tissue - composed of fiber tracts carrying impulses to, from, or within the cortex  Structural Classification - based on the number of processes, including both dendrites and axons, extending from the cell body - Multipolar neuron - several process - Bipolar neurons - with two process —one axon and one dendrite - Unipolar neurons - single process emerging from the cell body CENTRAL NERVOUS SYSTEM FUNCTION ANATOMY OF THE BRAIN - has four major regions: 1. CEREBRAL HEMISPHERES - collectively called as Cerebrum - the most superior part of the brain as this develop and grow, they enclose and obscure most of the brain, so many brain stem structures cannot normally be seen unless a sagittal section is made Gyri - elevated ridges of tissue that exhibits the entire surface of cerebrum Sulci - shallow grooves that separates gyri  Basal Nuclei - several “islands” of gray matter - buried deep within the white matter of the cerebral hemispheres - help regulate voluntary motor activities 2. - DIENCEPHALON/ INTERBRAIN sits atop the brain stem enclosed by the cerebral hemispheres major structures are:  Thalamus - encloses the shallow third ventricle of the brain - relay station for sensory impulses passing upward to the sensory cortex  Hypothalamus - makes up the floor of the diencephalon - important autonomic center - has a role in regulating body temperature, water balance, and metabolism - center for many drives and emotions  Epithalamus - forms the roof of the third ventricle - Pineal gland and Choroid plexus are the important parts of epithalamus 3. BRAIN STEM - about the size of a thumb in diameter and approximately 3 inches long - has many small gray matter areas - its structures are:  Midbrain - a relatively small part of the brain stem - extends from the mammillary bodies to the pons inferiorly  Pons - a rounded structure that protrudes just below the midbrain - have important nuclei involved in the control of breathing  Medulla Oblongata - the most inferior part of the brain stem - contains centers that control heart rate, blood pressure, breathing, swallowing, and vomiting - an important fiber tract area - the area where important pyramidal tracts cross over to the opposite side  Reticular Formation - a diffuse mass of gray matter that extends the entire length of the brain stem - neurons of this are involved in motor control of the visceral organs 4. CEREBELLUM - large, cauliflower-like that projects dorsally from under the occipital lobe of the cerebrum - has two hemispheres and a convoluted surface - provides the precise timing for skeletal muscle activity and controls our balance SPINAL CORD - a glistening white continuation of the brain stem - provides a two-way conduction pathway to and from the brain - a major reflex center - extends from the foramen magnum of the skull to the 1st or 2nd lumbar vertebra - cushioned and protected by meninges GRAY MATTER OF THE SPINAL CORD AND SPINAL ROOTS - looks like a butterfly or letter H in cross section - Dorsal/ Posterior Horns - two posterior projections - Ventral/ Anterior Horns - two anterior projections - gray matter surrounds the central canal of the cord which contains CSF PERIPHERAL NERVOUS SYSTEM - consists of nerves and scattered ganglia STRUCTURE OF A NERVE - Nerve - a bundle of neuron fibers found outside the CNS - Endoneurium - a delicate connective tissue sheath that surrounds each fiber - Perineurium - a coarser connective tissue that wrap groups of fibers to form Fascicles (fiber bundles) - Epineurium - a tough fibrous sheath that bound all the fascicles together to form the cordlike nerve CRANIAL NERVES - 12 pairs of this primarily serve the head and neck only the vagus nerves extends to the thoracic and abdominal cavities - most of it are mixed nerves - Optic, Olfactory, & Vestibulocohlear nerves purely sensory in function SPINAL NERVES AND NERVE PLEXUSES - each spinal nerve divides into  Dorsal Ramus  Ventral Ramus - rami contain both motor and sensory fibers AUTONOMIC/ INVOLUNTARY NERVOUS SYSTEM - the motor subdivision of the PNS that controls body activities automatically - composed of a specialized group of neurons that regulate cardiac muscle, smooth muscles, and glands - signals flood from the visceral organs into the CNS, and the ANS makes adjustments as necessary to best support body activities - has two arms:  Sympathetic/ Thoracombular Division - “fight-or-flight” system - mobilizes the body during extreme situations working at full speed not only when you are emotionally upset but also when you are physically stressed  Parasympathetic/ Craniosacral Division - ”rest-and-digest” - allows us to unwind and conserve energy - neurons of the cranial region send their axons out in cranial nerves to serve the head and neck organs - chiefly concerned with promoting normal digestion - serves body organs by receiving fibers from both divisions exceptions are most blood vessels and most structures of the skin, some glands, and the adrenal medulla (only receive sympathetic fibers) REFERENCE: Essentials of Human Anatomy & Physiology 12th Edition. Marieb, E.N & Keller, 2016. S.M. Boston : Pearson. (PDF) SPECIAL SENSES respond to stimuli involved in vision, hearing, balance, smell, and taste a variety of receptors, housed in special senses organs such as the eye, ear, and nose, help detect stimuli in your surroundings four traditional senses: smell, taste, sight, and hear Equilibrium = housed in the ear; fifth special sense Special sense receptors = either large,complex sensory organs (eyes and ears) or localized clusters of receptors (taste buds and olfactory epithelium)  Eyelids - protects the eye Eyelashes - projecting from the border of each eyelid - that EYE AND VISION nearly 70% of all sensory receptors in the body are here EXTERNAL AND ACCESSORY STRUCTURES Adult eye - 1 inch in diameter 1/6 of the eye’s surface is normally seen Accessory structures:  - 6 Extrinsic eye muscles - attached to the outer surface of each eye produce gross eye movements and make it possible for the eyes to follow a moving object Tarsal Glands - modified sebaceous glands associated with the eyelid edges; produce an oily secretion lubricates the eye  Conjunctiva delicate membrane; lines the eyelids and covers part of the outer surface of the eyeball secretes mucus which helps to lubricate the eyeball and keep it moist  Lacrimal apparatus consists of the lacrimal gland and a number of ducts that drain lacrimal secretions into the nasal cavity Lacrimal Glands - release a dilute salt solution/ tears onto the anterior surface of the eyeball through several small ducts Lacrimal canaliculi - tears flush across the eyeball into here medially - Lacrimal sac - provides passage of lacrimal fluid towards nasal cavity Nasolacrimal duct - empties lacrimal fluid into the nasal cavity Tears - contains mucus, antibodies, and lysozyme INTERNAL STRUCTURE EYEBALL a hallow sphere where its wall is composed of three layers and its inferior is filled with humors, a fluid that help to maintain its shape Lens - main focusing apparatus of the eye; supported upright within the eye cavity dividing it into two chambers A. LAYERS FORMING THE WALL: 1. FIBROUS LAYER outermost layer consists of the sclera and cornea  - Schlera thick white connective tissue seen anteriorly as the “white of the eye”  - Cornea well supplied with nerve endings where light enters the eye most exposed and very vulnerable to damage has the ability to repair itself beyond the reach of immune system 2. VASCULAR LAYER middle of the the eyeball has three distinguish regions  - Choroid a blood-rich nutritive tunic that contains a dark pigment, which prevents light from scattering inside the eye modified to form two smooth muscle structures:  Ciliary body attached to the lens by ciliary zonule  Iris has pupil through which light passes 3. SENSORY LAYER innermost of the eye delicate two-layered retina, which extends anteriorly only to the ciiary body - - Outer pigment layer - composed of pigmented cells that absorb light and prevent light from scattering inside the eye Inner neural layer - contains millions of receptor cells Photoreceptors - responds to light  Rods  Cones two neuron chain where electrical signals pass from the photoreceptors:  Bipolar cells  Ganglion cells Optic nerve - where electric signals pass to leave the retina B. LENS divides the eye into two segments or chambers: 1. ANTERIOR (AQUEAOUS) SEGMENT anterior to the lens contains Aqueous humor (clear watery fluid) which is similar to blood plasma and is continually secreted by a special area of the choroid 2. POSTERIOR (VITREOUS) SEGMENT posterior to the lens filled with Vitreous humor or vitreous body (gel-like substance) which helps prevent the eyeball from collapsing inward by reinforcing it internally OPHTHALMOSCOPE an instrument that illuminates the interior of the eyeball, allowing the retina, optic disc, and internal blood vessels at the fundus, or posterior wall of the eye, to be viewed and examined PATHWAY OF LIGHT REFRACTED when light passes from one substance to another substance that has a different density, its speed changes and its rays are bent Light rays are bent in the eye as they encounter the cornea, aqueous humor, lens, and vitreous humor ACCOMMODATION ability of the eye to focus specifically for close objects REAL IMAGE image formed on the retina as a result of the light-bending activity of the lens, that is reversed from left to right, inverted, and smaller than the object - accommodation pupillary reflex the pupils also constrict reflexively when we view close objects provides more acute vision OVERCONVERGING vision problems when lens is too strong - UNDERCONVERGING vision problems when lens is too week EAR: HEARING AND BALANCE VISION FIELDS AND VISUAL PATHWAYS TO THE BRAIN - Axons carrying impulses from the retina are bundled together at the posterior aspect of the eyeball and leave the back of the eye as the optic nerve OPTIC CHIASMA fibers from the medial side of each eye cross over to the opposite side of the brain MECHANORECEPTORS receptors that respond to physical forces such as sound vibrations HEARING APPARATUS allows us to hear an extraordinary range of sound HIGHLY SENSITIVE EQUILIBRIUM RECEPTORS keep our nervous system continually up to date on the position and movements of the head OPTIC TRACTS the fiber tracts that result are the optic tracts. ANATOMY OF THE EAR divided into three major areas - 1. EXTERNAL (OUTER) EAR involved with hearing only composed of: - the optic tract fibers synapse with neurons in the thalamus, whose axons form the optic radiation, which runs to the occipital lobe of the brain. There they synapse with the cortical cells, and visual interpretation, or seeing, occurs Each side of the brain receives visual input from both eyes. Each eye “sees” a slightly different view but that their visual fields overlap quite a bit. As a result of these two phenomena, humans have binocular vision (two-eyed vision) provides for depth perception, also called “three-dimensional” vision, as our visual cortex fuses the two slightly different images delivered by the two eyes into one “picture.” EYE REFLEXES CONVERGENCE the reflexive movement of the eyes medially when we view close objects PHOTOPUPILLARY REFLEX when the eyes are suddenly exposed to bright light, the pupils immediately constrict prevents excessively bright light from damaging the delicate photoreceptors A. AURICLE/ PINNA what most people call the “ear” shell-shaped structure surrounding the auditory canal opening B. EXTERNAL ACOUSTIC MEATUS or auditory canal short, narrow chamber carved into the temporal bone of the skull  Ceruminous gland - secretes earwax, which provides a sticky trap for foreign bodies and repels insects TYMPANIC MEMBRANE (EARDRUM) hit by sound waves after entering the auditory canal, that will cause it to vibrate canal ends of this separates the external from the middle ear - movement at the oval window sets the fluids of the inner ear into motion, eventually exciting the hearing receptors. 3. INTERNAL (INNER) EAR a maze of bony chambers called the bony labyrinth, or osseous labyrinth located deep within the temporal bone behind the eye socket three subdivisions of the bony labyrinth: 2. MIDDLE EAR or tympanic cavity small, air-filled, mucosa-lined cavity within the temporal bone flanked laterally by the eardrum and medially by a bony wall with two openings, oval window and the inferior, membrane-covered round window PHARYNGOTYMPANIC TUBE auditory tube runs obliquely downward to link the middle ear cavity with the throat, and the mucosae lining the two regions are continuous is normally flattened and closed, but swallowing or yawning can open it briefly to equalize the pressure in the middle ear cavity with the external, or atmospheric, pressure when the pressures are unequal, the eardrum bulges inward or outward, causing hearing difficulty and sometimes earaches. TYMPANIC CAVITY is spanned by the three smallest bones in the body Ossicles = transmit the vibratory motion of the eardrum to the fluids of the inner ear - A. HAMMER, OR MALLEUS when the eardrum moves, it moves the hammer - B. ANVIL, OR INCUS vibration from hammer transfers here - C. STIRRUP, OR STAPES anvil passes the vibration here, which presses on the oval window of the inner ear A. COCHLEA Spiraling, pea-sized B. VESTIBULE situated between the semicircular canals and the cochlea C. SEMICIRCULAR CANALS BONY LABYRINTH filled with a plasmalike fluid called Perilymph membranous labyrinth Suspended in the Perilymph a system of membrane sacs that more or less follows the shape of the bony labyrinth contains a thicker fluid called Endolymph EQUILIBRIUM equilibrium receptors of the inner ear, collectively called the vestibular apparatus can be divided into two branches: - A. STATIC EQUILIBRIUM static = rest MACULAE receptors within the membrane sacs of the vestibule that are essential to our sense of static equilibrium report on changes in the position of the head in space with respect to the pull of gravity when the body is not moving Because they provide information on which way is up or down, they help us keep our head erect are extremely important to divers swimming in the dark depths, enabling them to tell which way is up (to the surface) Each macula is a patch of receptor (hair) cells with their “hairs” embedded in the otolithic membrane (a gelatinous mass studded with otoliths) - - - - - As the head moves, the otoliths roll in response to changes in the pull of gravity. Bending activates the hair cells, which send impulses along the vestibular nerve to the cerebellum of the brain, informing it of the position of the head in space B. DYNAMIC EQUILIBRIUM found in the semicircular canals, respond to angular or rotational movements of the head rather than to straight-line movements the semicircular canals are oriented in the three planes of space within the ampullae, swollen regions at the base of each membranous semicircular canal, are multiple receptor regions, each called a Crista Ampullaris or simply Crista, which consists of a tuft of hair cells covered with a gelatinous cap called the Cupula When your head moves in an arclike or angular direction, the endolymph in the canal lags behind the movement. Then, as the cupula drags against the stationary endolymph, the cupula bends with the body’s motion. This stimulates the hair cells, and impulses are transmitted up the vestibular nerve to the cerebellum. Bending the cupula in the opposite direction reduces impulse generation When you are moving at a constant rate, the receptors gradually stop sending impulses, and you no longer have the sensation of motion until your speed or direction of movement changes Although the receptors of the semicircular canals and vestibule are responsible for dynamic and static equilibrium, respectively, they usually act together. sight and the proprioceptors of the muscles and tendons are also important in providing the cerebellum with information used to control balance. HEARING SPIRAL ORGAN OF CORTI the endolymph-containing membranous labyrinth of the cochlea within the cochlear duct contains the hearing receptors, or hair cells - the chambers (scalae) above and below the cochlear duct contain perilymph sound waves that reach the cochlea through vibrations of the eardrum, ossicles, and oval window set the cochlear fluids into motion As the sound waves are transmitted by the ossicles - - - - - - from the eardrum to the oval window, their force (amplitude) is increased by the lever activity of the ossicles nearly the total force exerted on the much larger eardrum reaches the tiny oval window, which in turn sets the fluids of the inner ear into motion, and these pressure waves set up vibrations in the basilar membrane The receptor cells, positioned on the basilar membrane in the spiral organ of Corti, are stimulated by the vibrating movement of the basilar membrane against the gel-like tectorial membrane that lies over them The “hairs” of the receptor cells are embedded in the stationary tectorial membrane such that when the basilar membrane vibrates against it, the “hairs” bend Because sound usually reaches the two ears at different times, we could say that we hear “in stereo.” Functionally, this helps us to determine where sounds are coming from in our environment. When the same sounds, or tones, keep reaching the ears, the auditory receptors tend to adapt,or stop responding, to those sounds, and we are no longer aware of them hearing is the last sense to leave our awareness when we fall asleep or receive anesthesia and is the first to return as we awaken. SMELL AND TASTE CHEMORECEPTORS the receptors for taste and olfaction are classified because they respond to chemicals in solution OLFACTORY RECEPTORS AND THE SENSE OF SMELLS OLFACTORY RECEPTORS receptors for the sense of smell occupy a postage stamp–sized area in the roof of each nasal cavity air entering the nasal cavities must make a 90° turn to enter the respiratory passageway below, so sniffing, which causes more air to flow superiorly across the olfactory receptors, intensifies the sense of smell olfactory receptor cells are neurons equipped with olfactory hairs, long cilia that protrude from the nasal epithelium and are continuously bathed by a layer of mucus secreted by underlying glands - olfactory nerve conducts the impulses to the olfactory cortex of the brain olfactory pathways are closely tied into the limbic System, thus, olfactory impressions are long-lasting and very much a part of our memories and emotions olfactory receptors are exquisitely sensitive—just a few molecules can activate them. olfactory neurons tend to adapt rather quickly when they are exposed to an unchanging stimulus, in this case, an odor TASTE BUDS AND THE SENSE OF TASTE - word taste comes from the Latin word taxare, which means “to touch, estimate, or judge.” TASTE BUDS receptors for the sense of taste, are widely scattered in the oral cavity of the 10,000 or so taste buds that we have, most are on the tongue. A few are scattered on the soft palate, superior part of the pharynx, and inner surface of the cheeks The taste buds are found on the sides of the large round vallate papillae, or Circumvallate Papillae, on the tops of the more numerous Fungiform Papillae and in the Foliate Papillae on the sides of the tongue specific receptor cells that respond to chemicals dissolved in the saliva are epithelial cells called Gustatory cells The dorsal tongue surface is covered with small peglike projections, or papillae