Exam 2 Study Guide Chapter 4 Tissues

Exam 2 Study Guide Chapter 4: Tissues Tissues: group of cells that are similar in structure & perform a common or related function. 4 Primary Tissue Types:     Epithelial Tissue: coverings. Connective Tissue: binds & supports. Muscle Tissue: movement. Nervous Tissue: control. Developmental Aspect of Tissues: 3 Primary Germ Layers are formed. 1. 2. 3. Ectoderm: nervous tissue. Mesoderm: muscle & connective tissue. Endoderm: inner lining of digestive system. a. Epithelial Tissue comes from all 3 layers. Epithelial Tissue: sheet of cells that covers a body surface or lines a body cavity.   Covering & Lining Epithelium: forms outer layer of skin, urogenital tract, digestive tract, respiratory system, covers walls & organs of the closed ventral body cavity. Glandular Epithelium: makes glands of body. Functions of Epithelial Tissue:       Protection Absorption Filtration Excretion Secretion Sensory Reception Special Characteristics of Epithelial Tissue: 1. 2. 3. 4. 5. Polarity: all epithelia have 2 surfaces. a. Apical Surface: free surface exposed to body exterior or cavity of an internal organ. b. Basal Surface: lower surface that is attached to body. i. Basal Lamina: under basal surface, acts as a filter for molecules diffusing into epithelium from connective tissue below. Specialized Contacts: epithelial cells fit close together by tight junctions & desmosomes to form sheets. Supported by Connective Tissue: under basal lamina is reticular lamina, part of underlying connective tissue. The 2 lamina form basement membrane of epithelium. Avascular (no vessels) & Innervated (has nerve fibers). Regeneration: has a high regenerative capacity. Classification of Epithelia:  Simple: single layer of cells that functions in absorption, secretion & filtration. Exam 2 Study Guide  Stratified: 2 or more layers of cells that functions in protection. Cell Types: squamous, cuboidal, columnar. Simple Epithelia: 1. 2. 3. Simple epithelia function mostly in absorption, secretion, and filtration. Simple epithelia consist of a single cell layer. Simple epithelia are not protective. Stratified Epithelia: 1. 2. 3. Stratified epithelia have 2 or more cell layers. They regenerate at the basement membrane and migrate upward. Stratified epithelia are durable and their main function is for protection. Exam 2 Study Guide Glandular Epithelia: one of more cells that make & secrete a product (secretion).  Classified by 2 traits: o Where they release their product (endocrine/exocrine). o Cell number (unicellular/multicellular). Endocrine Glands: ductless glands.  Produce hormones excreted by exocytosis, enter blood stream, transported to target organ. Exocrine Glands: have ducts. Secrete products onto body surfaces or into body cavities.   Unicellular Exocrine Glands: mucous or goblet cells- produce mucin (mucus). Found in epithelial linings of intestinal & respiratory tracts. Multicellular Exocrine Glands: many celled glands with 2 parts. o Epithelium derived duct o Secretory unit/secretory cells o Classified by structure & type of secretion  Simple glands (unbranched duct) or compound glands (branched duct)  Cells: tubular, acinar or tubuloacinar  Type of Secretion:    Merocrine: (most) secrete products by exocytosis. Holocrine: accumulate products within then rupture. Apocrine: accumulate products within but only apex ruptures. Connective Tissue: most abundant & widely distributed tissue in body.  1. It binds together, supports, and strengthens other body tissues. 2. It protects and insulates internal organs and stores fuel. 3. It compartmentalizes structures such as skeletal muscles. 4 Main classes: Connective Tissue Proper, Cartilage, Bone & Blood. Exam 2 Study Guide Common Characteristics of Connective Tissue: 1. 2. 3. Common origin Degrees of vascularity Extracellular matrix 3 Main Elements of Connective Tissue: 1. 2. 3. Ground Substance: unstructured material that fills the space between cells & contains fibers, composed of interstitial fluid, cell adhesion proteins & proteoglycans. Fibers: collagen, elastic, reticular. Cells: blast cells Connective Tissue Fibers: 1. 2. 3. Collagen Fibers: very tough & provide high tensile strength to the matrix. Elastic Fibers: long thin fibers that form branching networks in the matrix, provide stretch & recoil properties. Reticular Fibers: short, fine, collagenous fibers, surround small blood vessels & support the soft tissue of organs. Connective Tissue Cells:   Blast Cells: actively mitotic cells that secrete the ground substance & the fibers that make up the matrix Include: o Connective Tissue Proper: Fibroblasts. o o     Cartilage: Chondroblasts. Bone: Osteoclasts. o Blood: Hematopoietic Stem Cells. Fat Cells or Adipocytes: store nutrients. White Blood Cells: respond to tissue injury. Mast Cells: detect foreign microorganisms and initiate the inflammatory response to them. Macrophages: phagocytize foreign molecules & particles (part of immune system). Connective Tissue Proper:  Loose Connective Tissue: o Areolar Connective Tissue: supports/binds other tissues, holds body fluids, defend against infection, stores nutrients as fats. Cell types: FIBROBLASTS. Most widely distributed connective tissue in body. o Adipose Tissue: provide reserve food fuel, insulates against heat loss, supports/protects organs. Cell type: ADIPOCYTES. o Reticular Connective Tissue: Fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages, found in lymphoid organs, Cell type: RETICULAR CELLS.  Dense Connective Tissue Exam 2 Study Guide o o o Dense Regular Connective Tissue: Attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction. Cell type: FIBROBLASTS. Dense Irregular Connective Tissue: Withstands tension exerted in many directions; provides structural strength. Cell type: FIBROBLASTS. Elastic Connective Tissue: allows tissue to stretch & recoil. Cell type: FIBROBLASTS. Cartilage: stands up to both tension and compression; it is tough but flexible.   Chondroblasts which produces new matrix in growing cartilage Chondrocytes are mature cartilage cells that maintain the matrix, they are found in little shallow pits called lacunae. Hyaline Cartilage: most abundant in body, Contains large amounts of collagen fibers, cell type: CHONDROCYTES. Elastic Cartilage: Looks like hyaline cartilage but has elastic fibers that are visible. Cell type: CHONDROCYTES. Fibrocartilage: Has rows of collagen fibers that alternate with rows of chondrocytes, compressible and resists tension well. Bone: Also called osseous tissue, Made up of collagen fibers and calcium salts which makes it hard. Exam 2 Study Guide   Osteoblasts produce the matrix. Osteocytes maintain the matrix, they also reside in lacunae. Blood: classified as a connective tissue because it develops from mesenchyme and it consists of blood cells surrounded by a fluid matrix called plasma.  Cell Types: o Red Blood Cells o White Blood Cells o Platelets Muscle Tissue: Highly cellular, well vascularized tissues that are responsible for most types of body movements. Contain myofilaments: bring about muscle contraction. Skeletal Muscle:     Bundles of muscle cells, called muscle fibers Skeletal muscle is voluntary Skeletal muscle cells are multinucleate The fibers are striated due to the arrangement of the myofilaments Cardiac Muscle:      Found in the walls of the heart Cardiac cells are uninucleate Striated due to the arrangement of the myofilaments Contain intercalated discs which are like desmesomes Involuntary Smooth Muscle:     Have no striations but do have myofilaments Are uninucleate Cells are spindle shaped and occur in sheets involuntary (A) Skeletal Muscle (B) Smooth Muscle (C) Cardiac Muscle Nervous Tissue: tissue of the nervous system which includes the brain and the spinal cord and its nerves. Exam 2 Study Guide     Neuroglia – support cells Neurons – cells that generate and conduct impulses Each neuron contains processes that respond to stimuli called dendrites. Each neuron contains a process called an axon that transmits impulses within the body. Covering & Lining Membranes: 1. 2. 3. Cutaneous Membrane: skin Mucous Membrane: lines cavities that open to the outside of body, secrete mucus, found in respiratory, digestive, urinary & reproductive systems. Serous Membrane: simple squamous epithelium (mesothelium), lines cavities not open to exterior. Tissue Repair: 1. 2. Regeneration: replaces destroyed tissue with the same kind of tissue. Fibrosis: fibrous connective tissue proliferates to form scar tissue. Chapter 5: Integumentary System Integument: an enveloping layer of an organism or one of its parts. Exam 2 Study Guide Skin is the largest organ in the human body. Integumentary system: skin, sweat glands, sebaceous glands, hair, nails. Skin is composed of 3 layers: Epidermis & Dermis. Characteristics of the skin: Dermis=vascularized. Epidermis=avascular. Epidermis: keratinized stratified squamous epithelium with 4 cell types & five layers.      Stratum Corneum: 25-30 rows of dead cells, continuously shed & replaced. Stratum Lucidum: not present on hairy skin- only palms & soles of feet. Statum Granulosum: develops precursor of keratin. Stratum Spinsoum: tightly joins lower & upper layer. Stratum Basale: produces stem cells that produce melanocytes & keratinocytes. Cell types:     Keratinocytes: produce keratin. (Keratin is a fibrous protein that gives skin its protective properties.) Melanocytes: cells that synthesize melanin. (Melanin creates protective shield against the sun.) Dendritic Cells: inject foreign substances & activate immune system. Tactile (Merkel) Cells: functions as a sensory receptor for touch. Dermis: connective tissue proper containing fibroblasts, macrophages mast cells & white blood cells. Contains sweat glands, oil glands & hair follicles. 2 layers: Papillary & Reticular.   Papillary layer: above reticular layer. Made of areolar connective tissue. Contain small blood vessels that can diffuse nutrients to epidermis above. o Dermal papillae: peg-like projections that indent overlying epidermis that contain capillary loops, free nerve endings & tactile (Meissner’s) corpuscles (touch receptors). Reticular layer: contain dense irregular connective tissue & accounts for 80% of dermis. Skin Color: 1) Melanin: all humans have about the same #, differences in skin color reflect the kind & amount of melanin made & retained. 2) Carotene: yellow-orange pigment, most obvious in soles of feet & palms. 3) Hemoglobin: pinkish hue of fair skin which comes from oxygenated blood in dermal capillaries. Hair & Hair Follicles: shaft (where keratinization is complete) & root (where keratinization is ongoing). Hair Layers (in-out): medulla, cortex, cuticle. Hair pigment is made by melanocytes at the base of the hair follicle & transferred to cortical cells. Sweat (Sudoriferous) Glands: cover entire skin surface except nipples & genitalia. Contain myo-epithelial cellsspecialized cell that contracts by nervous system stimulation to expel sweat onto skin. 1) Eccrine (Merocine) Glands: located all over body, heavy on palms, soles & forehead. a. Secrete sweat by exocytosis. Exam 2 Study Guide b. Sweating is controlled by sympathetic division of autonomic nervous system to keep body temperature from getÝng too high. 2) Apocrine Glands: confined to axillary & anogenital areas. Like merocrine glands but they secrete their product into hair follicles. a. Product is same as sweat with fatty substances & proteins added. Odorless upon secretion but when it comes into contact with bacteria on skin, it produces body odor. b. Don’t function until puberty. Do not contribute to temperature regulation & are stimulated during pain & stress. Other Glands: 1) Ceruminous Glands: secrete cerumin (earwax). 2) Mammary Glands: secrete milk. Sebacous (Oil) Glands: simple branched alveolar glands found all over body except palms & soles. Secrete an oily substance- sebum.   Holocrine gland- secrete product when the gland becomes engorged the bursts & liquid & cell fragments constitute the oil. Contraction of erector pili muscles forces the oil out of the follicle. Sebum works to soften the skin & hair & slows water loss. Functions of Integumentary System: 1) Protection: physical, biological & chemical barrier. 2) Body temperature regulation: skin secretes sweat to maintain body temp in homeostatic state. Blood is shunted to skin when temp goes up & shunted to core when temp goes down. 3) Metabolic function: skin creates modified cholesterol molecule that is a precursor for Vitamin D. It is stimulated by sunlight. Makes proteins, activates some steroid hormones, etc. 4) Blood reservoir: holds about 5% of the body’s entire blood volume. 5) Excretion: body eliminates wastes in sweat (uric acid, urea, ammonia). Skin Cancer: 1) Basal Cell Carcinoma (least malignant) 2) Squamous Cell Carcinoma 3) Melanoma (Most malignant) Burns: tissue damage inflicted by intense heat, electricity, radiation or certain chemicals, which denature cell proteins & kill cells in the affected areas.     Immediate threat to life- catastrophic loss of body fluids containing proteins & electrolytes. Can lead to dehydration & electrolyte imbalance… which then leads to renal failure & circulatory shock. First degree burn: only epidermis is damaged. Second degree burn: injures epidermis & upper region of dermis, produce blisters. Third degree burn: entire epidermis & dermis, threat of infection. Chapter 6: Bone Tissue & Skeletal System Exam 2 Study Guide Skeletal Cartilage is made up of cartilage tissue: hyaline cartilage, elastic cartilage, fibrocartilage. Cartilage contains no blood vessels or nerves. Cartilage is surrounded by perichondrium where nutrient diffuse into cartilage. Hyaline Cartilage: most abundant skeletal cartilage. 4 types: 1) 2) 3) 4) Articular Cartilage: covers ends of long bones at moveable joints. Costal Cartilage: connects ribs to sternum. Nasal Cartilage: supports the external nose. Respiratory Cartilage: larynx, bronchi & trachea. Elastic Cartilage: only found in external ear & epiglotÝs. Fibrocartilage: highly compressible with great tensile strength, found in knee meniscus, intervertebral discs, and pubic symphasis. Cartilage Growth: 1) Appositional Growth: cartilage forming cells in the perichondrium secrete new matrix against the external face of the existing cartilage tissue. Bones increase in thickness! 2) Interstitial Growth: the lacunae bound chondrocytes divide and secrete new matrix, expanding the cartilage from within. Axial Skeleton: skull, vertebral column & rib cage. Appendicular Skeleton: bones of upper/lowers limbs, shoulder, & hips that attach limbs to axial skeleton. Functions of Bones: Support, Protection, Movement, Mineral & Growth Factor Storage (bone is resovoir for minerals- calcium & phosphate mostly), Blood Cell Formation (most hematopoiesis occurs in red marrow), Triglyceride (fat) formation (fat is stored in bone cavities), Hormone Production (produce osteocalcin- protects against obesity, glucose intolerance & diabetes mellitus). Compact Bone: dense outer layer that looks solid & smooth. Spongy Bone: internal bone tissue made of trabeculae. Periosteum: external covering of bone. Secured to bone matrix by collagen fibers called Perforating (Sharpey’s) Fibers. 1) Fibrous layer: dense outer layer 2) Osteogenic layer: inner layers consists of stem cells that give rise to all bone cells except osteoclasts. Endosteum: found on internal bone surface, covers trabeculae of spongy bone, in marrow cavities. Diploe: spongy bone in flat bones. Red marrow in FLAT and IRREGULAR bones is the most active!! Bone Cells: Exam 2 Study Guide 1) 2) 3) 4) Osteocyte: maintain bone matrix. Osteoblast: form bone. Osteoprogenitor Cell: stem cell whose divisions produce osteoblasts. Osteoclast: reabsorb (dissolve) bone. Osteon (Haversion System): structural unit of compact bone.  Each matrix tube is called a lamella. An osteon is made up of layers of lamella. Central Canal: runs through the core of each osteon and contains blood vessels with an artery, nerve and vein. Perforating (Volkmann’s) Canals: lie at right angles to the long axis of the bone and connect the blood and nerve supply of the periosteum to those in the central canals and the medullary cavity. Canaliculi: canals that connect lacunae to each other & to central canal. Interstitial Lamellae: life between osteons to fill in spaces created by circular osteons. Circumferential Lamellae: just deep to the periosteum extend around the entire circumference of the diaphysis. Chemical Composition of Bone: 1) Organic: bone cells & osteoid- provide the structure and the flexibility and tensile strength that allow it to resist stretch and twisting. 2) Inorganic: mineral salts- consist of hydroxyapatites, or mineral salts, provide bone its hardness. Ossification: process of bone formation. 1) Endochondral Ossification: a bone develops by replacing hyaline cartilage resulting in a cartilage or endochondral bone. 2) Intramembraneous Ossification: a bone develops from a fibrous membrane and the bone is called a membrane bone. Forms cranial bones of skull & clavicles. Epiphyseal Plate Closure: Longitudinal bone growth ends when mitosis slows down and the epiphyseal plate becomes thinner and thinner until the epiphysis and the diaphysis fuse and leaves a line where the plate formally was. Occurs about age of 18. Hormone Regulation of Bone Growth: 1) Growth Hormone: the most important stimulus of epiphyseal plate activity in children. 2) Thyroid Hormones: modulate the activity of growth hormone, ensuring that the skeleton has proper proportion as it grows. 3) Testosterone & Estrogen: promote the growth spurt that occurs on adolescence, they promote the masculinization and feminization of specific parts of the skeleton, later they induce epiphyseal closure.