Vet Tech Notes

Intro to Vet Tech.              Outline: chapter 1: Basic Cell Biology Cell Make-Up: The cells and their structures are composed of molecules. Biochemistry is the study of these molecules in living creatures. Lipids: Or fats combined hydrogen, carbon, and oxygen in a form that is poorly dissolved in water. (This is why fat floats to the top of water.) Fat consists of a molecule of glycerol and three fatty acid molecules. Fats are stored in the cell body as a source of high energy. Phospholipids are similar but have only two fatty acid groups, and a phosphate group (PO 4) Significant because one end is (Hydrophilic) meaning it is attracted to or soluble in water. The other end is (hydrophobic) repels water. Carbohydrates have a genetic material within the cell; five- carbon sugars ribose and deoxyribose. Glucose: (blood sugar), a six carbon sugar used for energy in the cells. Diabetes: The blood sugar increases to very high levels, but the animal does not utilize it properly. Polysaccharides are composed of many monosaccharides. Glycogen: A polysaccharide starch, which is used to store energy within the cell. Glycogen is made when monosaccharides are taken into the cell and then assemble into a long chain. Polysaccharides + Protein molecules = Glycoproteins. (Assist to build the cell structure) Proteins make up 50% of the dry weight of animals. Proteins are large molecules of amino acids. Enzymes: are protein molecules that speed up the chemical reactions in the body. Proteins found in blood help to carry oxygen, stop bleeding, and fight off infection these are called Antibodies. Ribonucleic acid (RNA) Deoxyribonucleic acid (DNA) Both DNA and RNA have a backbone of sugar alternating with phosphate. DNA: A double stranded molecule formed as the bases are loosely bounded together. The molecule has a twisted structure, which is described as a double helix. A group of three nitrogenous bases is the code for a specific amino acid. The order of nitrogenous bases makes up the genetic code of an animal. Each gene provides a code for each peptide chain.  Cell Structure: Specialized structures within the cells are not called organelles. The cell membrane (plasma membrane) is common in all cells; it serves as the boundary keeping the inside of the cell contained. Cell membranes are semipermeable meaning they allow certain substances but not others to pass. The contents of a cell are divided into the nucleus and the cytoplasm. Cytoplasm is the organelles and fluid in the cell.  The nucleus contains the genetic material such as DNA of the cells, which controls cellular activities by coding for protein synthesis.  DNA in the nucleus is called chromatin. A membrane of two lipid bilayers surrounds the nucleus.  This membrane is often connected to other organelles such as the endoplasmic reticulum and ribosomes. Endoplasmic reticulum : a collection of folded membrane, which is often attached to the nucleus.  Ribosomes often line the membrane, giving it a bumpy appearance that’s where the name Rough endoplasmic reticulum (RER) comes from.  Proteins produced by the ribosomes are deposited into the rough ER.  Smooth Endoplasmic reticulum (SER) has no ribosomes attached , this is not common.  Liver cells contain large amounts of SER.  SER cells produce glycogen and lipids, and removes toxins. Golgi apparatus: formed when large amount s of folded membrane that looks similar to the SER.  Produces polysaccharides and special protein sacs called lysosomes.  Proteins produced in the RER are sent to the Golgi apparatus; proteins are then changed and collected in the lysosomes. Proteins collected in the lysosomes are Enzymes.  Lysosomes contain enzymes that help to break down other molecules.  Lysosomes are used to digest food taken in by the cell and to destroy cell structures that are no longer needed.  Cells that die in the body are released into the cytoplasm. Mitochondria: small rod- shaped organelles found in varying numbers in cells.  The more active the cell the more mitochondria that can be found.  Converts food substances into energy that can be used by the cell. (Known as the power house of a cell) Cell Function: Metabolism: Describes all the reactions going on in the cell. Can be categorized by two main parts.  Anabolism: describes reactions in which smaller molecules are combined into larger ones. (EX: the joining of amino acids to form proteins.)  Catabolism: the opposite, occurs when large molecules are broken down into smaller ones. (EX: the breaking down of glycogen to release energy.) A liquid called extracellular fluid (ECF) surrounds living cells.  Water is the major component of ECF, conversely, carbon dioxide passes from the cells through it. Diffusion: random movement of molecules allows equalization of concentrations across a membrane. Active transport: Energy is used to actively pump molecules into a region of higher concentrate. Endocytosis: A large particle is engulfed by the cell membrane and brought into the cytoplasm within a vacuole. Exocytosis: A membrane- bound sac joins with the cell membrane to release the particle. 5 Protein Synthesis: Transcription of mRNA: RNA polymerase separates the strands of DNA and creates a strand of mRNA coded by the nucleotides of the DNA molecule. Mitosis and cancer: Cell division is controlled by a number of factors present in the cell and extracellular fluid. Uncontrolled mitosis results in in cancer, new cells are produced to quickly- they accumulate and form a tumor. The steps of cell division are broken down into four stages:  Interphase  Prophase  Metaphase  Anaphase  Telophase. A few specialized cells such as nerve and muscle cells have very limited or no ability to divide. Mammalian Reproduction: In sexual reproduction the sperm and egg cell join to form the new embryo. In this process, half the genetic material is provided by each of the cells.  Meiosis is the division in which the resulting cells contain only half the genetic material.  The final result of meiosis is the formation of four cells, each with half the number of chromosomes. The phases of meiosis include:  Early Prophase I (Leptotene)  Middle Prophase I (Zygotene)  Late Prophase I (Diplotene) o Homologous chromosomes align in the center of the cell. The Homologous exchange segments of genetic material.  Metaphase I o Similar to the step in mitosis, except that the homologous will separate into opposite cells.  Anaphase I o The chromosomes move to opposite ends of the cell.  Telophase I o The Cell is divided into two daughter cells, each with half the chromosome numbers of the original cell.     Prophase II Metaphase II Anaphase II Telophase II Clinical practice: In clinical practice, the appearance of the cell is often evaluated. A biopsy takes tissues or cells from an animal for microscopic review. Tumors are a mass in tissue or organs.  Benign: A tumor that is localized in one are, have a well-defined margin, and don’t spread to other parts of the body.  Malignant: A tumor that is more likely to invade surrounding tissue and spread to other parts of the body. Pathologists: Doctors who interpret and diagnose changes in cells and tissues. In cancer cells there is often a large nucleus or many nucleoli. Outline: Chapter 2: Tissue types and functions Epithelial Tissues: Epithelial tissues are collections of cells packed together in sheets.  The sheets line the body’s surface and openings including of the intestinal, reproductive, and urinary tracts.  They also line the tubes in the body such as blood vessels and the heart.  Epithelial tissues help in many ways such as protecting skin from trauma and sun.  Keep substances from entering the body and also conserve materials within the body.  Provide senses to parts of the body. o The retina in the eye is a specialized epithelial layer that helps to transmit the visual input to the central nervous system. o The tongue has receptors for taste, touch, and temperature. Basement Membrane: A collection of fibers that ties the epithelial layer to the underlying tissue. Epithelial tissue classifications: 1. Simple, with one cell layer 2. Stratified, with multiple layers 3. Transitional, with multiple layers (The shape of the cell can change.) Descriptive terms to identify shape of a cell: 1. Squamous (very flat) 2. Cuboidal (Cubed shape) 3. Columnar (More tall and wide) Two terms are combined above to describe a epithelial cell.  Ex: a simple squamous epithelial cell contains a single layer flat cell. These cells can be so thin that the nucleus bulges in the surface of the cell. o Can be found at in blood vessels, allowing for transfers of nutrients, fluids, gasses, and wastes. Endocrine glands secrete hormones which are distributed to other regions of the body via blood stream.  Endocrine glands release the product directly into the blood stream without having internal ducts or tubules. o Ex: The thyroid, adrenal, and pituitary glands are all endocrine glands. Exocrine glands do have ducts which transport their secretions to impact more local areas.  Hormones produced do not enter the circulation. o Ex: sweat and salivary glands. Integument: Skin Keratin: a specialized protein. Connective Tissue: Tendons, fat, blood, and cartilage are all examples of connective tissue.    Tendons: Serve to connect muscle to bone Ligaments: connects bones to bones. Cartilage contains no blood vessels and is nourished by a surrounding fluid. Adipose Tissue: Another form of connective tissue consists of cells filled with lipid.  Adipose tissue can be found behind the eye, within bone marrow and in the abdomen. Blood is considered to be a special type of connective tissue; the cells are suspended in a large volume of liquid matrix called plasma. Red blood cells transport oxygen and carbon dioxide, white blood cells fight infections. Muscle Tissues: Muscles allow animals to move; there are three types of muscles:  Skeletal  Smooth  Cardiac Smooth muscle (involuntary muscle) can be found in many of the hollow organs in the body, including the gastrointestinal tract, urinary bladder, and blood vessels. Skeletal Muscle is a striated voluntary muscle. Such as the Achilles tendon.  A muscle consists of thousands of fibers, or muscle cells.  An entire muscle cell is called a Myofiber. Porcine Stress Syndrome: (PSS) is a genetically transmitted disease in pigs in which calcium is not transported back it to the endoplasmic reticulum.  This causes the muscle to not relax normally. Rigor Mortis: (Muscle stiffness) occurs after death because there is no supply of energy to pump calcium back into the Endoplasmic reticulum.  Without energy the muscle cannot relax so they remain stiff. Cardiac muscle is also striated in appearance but is involuntary action.  Cardiac muscles have the unique ability to initiate their own contractions. Nerve Tissues: Nerves allow communication among areas of the body by receiving and transmitting electrical signals.  Nerve tissues are found in the Brain and spinal cord. Central nervous system is made up of the brain and the spinal cord. Peripheral nervous system includes all the nerves outside of the central nervous system. Nerve tissue contains cells called neurons.  The body of the neuron houses the nucleus and many other organelles  The axon the hair like extension from the cell body carries the nerve impulses.  Axons many neurons bundled together create a nerve. The nerve impulses occur as a flow of ions passes through the cell membrane. There are three basic types of neurons: 1. Sensory neurons: theses neurons have receptors that are stimulated in response to changes in the animal’s environment. 2. Interneurons: These neurons are found within the central nervous system. 3. Motor neurons: these neurons begin in the central nervous system and extend to the muscle or glad. Clinical Practice: Certain infectious diseases may infect different tissue types.  Ex: foot and mouth disease is attracted epithelial tissues; it is highly infectious and can spread rapidly. Monday morning disease/ Tying up: common in horses, it often occurs on a Monday after a weekend of rest, when the horse consumes a full diet. After working out or exercising the horse will develop severe cramping.  Can result in damaged muscle tissue and kidneys. Outline: Chapter 3: The Musculoskeletal System Musculoskeletal System Functions: Bones furnish five basic functions:  Structure  Longevity  Protection  Mineral reserves  Blood cell protection The most visible function of bones is structure, which collected together forms a skeleton. Bone Structure: The bone structure is the framework for the shape and size of an animal. The structure of a bone contains many different fibers.  The compact bone, within the compact bone lies a more loosely arranged bone, called spongy or cancellous bone.  Spongy bone is found within long bones but not flat bones. (EX: not in the skull or pelvis)  Spongy bone is made of tiny spicules and plates of bone. Bones are covered with a thin connective tissue called the periosteum.  Periosteum is the source of blood vessels that supplies the nutrients to the bone tissue.  Periosteum blends into tendon and ligaments, binding them to the bone.  Periosteum does not cover bone portions which have cartilage. Bone is composed of a collection of microscopic units called osteon or haversion systems.  Within the center of the osteon is a haversion canal, which blood vessels, nerves, and lymphatics run through.  Many osteons are joined together to form the bone. Joint types and movements: Joints form where other tissues join two bones. Types of joints:  Fibrous Joints: The bones in a fibrous joint are brought together with a dense connective tissue. Also called fixed joints because little movement is possible. This joint can be found in the skull, where it is called a suture  Cartilage Joints: The bones in the joint are connected to cartilage. A cartilage joint occurs between two vertebrae and includes the intervertebral disk.  Synovial Joints: Synovial joints are the true moveable joints. It’s a dense layer of bony, and at the joint it’s covered in cartilage. The joint is enclosed with a joint capsule. The outer layer of the joint capsule contains strong connective tissue. Flexion: occurs when the angle between the two bones gets smaller. Extension: The opposite of flexion, occurs as the angle between the bones increases. Abduction: occurs when a part is moved away from the body. Adduction: occurs when a part is moved toward the body. Rotation: when a part spins on its axis. Circumduction: a movement in which the end of a limb is moved in a circular motion. Axial and Appendicular Skeletons: Axial Skeleton: contains the skull, vertebrae, ribs, and sternum. Appendicular Skeleton: Consists of the bones of limbs.  The appendicular skeleton includes the bones of the forelimbs and hind limbs.  Horses have fewer bones in the distal limbs than dogs do. The skull (cranium) found in the axial skeleton contains Nemours flat bones (About 50 in the dog). The vertebral column extends through the length of the body from the skull, and protects the spinal cord and allows movement.  The Vertebral column is broken down into anatomic divisions. The Thoracic vertebrae are found in the next division of the spinal column.  There is one set of ribs for each Thoracic vertebra.  Bones of the thorax protect the heart and lungs. The Lumbar Vertebrae, located in the lower back between the Thoracic vertebrae and the pelvis, this area flexes and extends as an animal runs.  The muscles of the abdomen attach these vertebras, forming a sling to hold in the internal organs. The Sacrum, a group of three Sacrum vertebrae fuses to support the pelvis. The Sacrum then forms with the pelvis, allowing the hind limbs to support the weight of the body. The Caudal or Coccygeal Vertebrae are small and comprise of the tail. The Humorous is the upper bone of the fore limb which is connected to the Scapula through a ball socket joint, allowing a wide range of motions.  The humorous then joins the elbow with the radius and the ulna. Number of carpal bones:    Dogs: 7 Ruminants: 6 Horses: 7 or 8 Bone Growth and remodeling: A long bone such as the femur divides into the shaft, or diaphysis, and at the ends, the epiphysis.  In young animals a cartilage plate separates the diaphysis from the epiphysis.  These growth plates or epiphyseal plates are the sights of elongation. Ossification: is the process when osteoblasts move into the cartilage and replace it with bone tissue, this involves more than just minerals to be deposited. X-rays: a form of electromagnetic radiation that can pass through living tissue. Radiology: the study of radiographs is an essential part of veterinary and human medicine. Relation of bones, muscles, and movement: Bones and muscles together provide the ability to move.  Each level of muscle is covered in connective tissue, which combines to form a tendon.  Some muscles end so closely to the bone no tendons can be seen.  Muscles are often arranged in groups to achieve a single function. o EX: three muscles make up the hamstrings (Biceps femoris, semimembranosus, and semitendinosus.) these muscles work together to extend the hip and flex the knee. Clinical Practice: Simple Fracture: A bone broken in two pieces, a clean break. Comminuted Fracture: A result in several fragments of bone. Compound (open) fracture: when one bone end punctures through the skin. Bone infection higher in this type of situation. In order for a fracture to heal the bone ends must be put back in alignment and held without movement. (Casts or even bone plates threw surgery) Intramedullary pin: a method of repairing ab broken bone in which a stainless steel pin is inserted into the medullary cavity. Hip dysplasia: Commonly occurred in dogs, in this condition the ball socket joint of the hip becomes diseased, causing the hip socket to become shallow. Degenerate joint disease: When a joint becomes so worn that the cartilage lining in the joint becomes thin and roughens. Joint ill: Occurs when bacteria enters a newborn’s body through the umbilical opening and settles in the joints, with lameness resulting Outline: Chapter 4: The Circulatory System Blood components and functions: Blood separates into a fluid portion and a formed- element protein. If blood is placed in a tube and spun the formed elements settle to the bottom of the tube, with the plasma left on top. The protein portion of the blood can be dived into three types:  Albumin: The major protein in the blood, maintains the water in the blood stream.  Globulins: A protein in the plasma, which is antibodies produced to fight off diseases.  Fibrinogen: Aids in clotting blood. Formed elements in the blood are divided into three fractions:  Red Blood Cells: Carry oxygen, Mature red blood cells do not have a nucleus. RBC’s are produced in the bone marrow.  White blood cells (Leukocytes): Are present to help fight off infections. White blood cells are also produced in the bone marrow, yet they spend little time in the blood stream and more time in tissues to fight off infections. WBC’s have a single nucleus. Five major types of White blood cells which can be divided into two major classes. o Granulocytes: Neutrophils, eosinophils, and Basophils. o Agranulocytes: Lymphocytes and monocytes.  Platelets: Also produced in the bone marrow, aid in the normal clotting of blood. Mammalian Heart Structures: Mammals have a four chambered heart. This provides for two separate circulatory paths.  The Pulmonary side: where the blood pumps to the lungs to exchange oxygen and carbon dioxide.  Systematic Circulations allows blood rich in oxygen and nutrients to circulate through the entire body, and organs. Blood Vessels and Blood flow: The Cranial (relating to the head) vena cava brings blood from structures in front of the heart. The Caudal (Relating to the tail) Vena cava returns blood from structures behind the heart. The Inferior vena cava corresponds to the caudal vena cava, delivering blood from organs below the heart. The superior vena cava delivers blood from organs above the heart. Electrocardiograms, Heart sounds, and Blood Pressure: In mammals the pacemaker is called the sinoatrial (SA) node. This specialized group of muscle cells is found in the right atrium, close to the cranial vena cava. The Atrioventricular (AV) node picks up the electrical impulses from the SA; this node is found close to the junction between the atrium and the ventricle. Cardiac Cycle: One complete contraction and relaxation of the heart. Systole: Contraction phase of the Cardiac cycle. Diastole: Relaxation phase of the Cardiac Cycle. Electrocardiograph: Electronic instrument that picks up the small electrical signal that runs through the body. Electrocardiogram: Tracing made by the electrocardiograph. Arrhythmia: Any changes in rate, rhythm or conduction within the heart. Tachycardia: Elevated heart rate. Cardiopulmonary Resuscitation (CPR): Procedure used to stimulate the heart to deliver oxygen to the lungs. The first heart sound, Lub, is created as the ventricles contract. The second heart sound, Dup, occurs when the ventricles relax. Heart Failure: Condition in which the heart cannot meet the demands of the animal. Hypo- : Below normal Hyper-: Above Normal -emia : levels in the blood stream Anemia: is a term used to describe a low red blood cell count.  Three basic causes of anemia include excessive blood loss, shortened life span of red blood cells, and decreased production of red blood cells. Autoimmune Disease: a condition in which the body’s immune systems destroys its own cells. Shock: Not enough blood is being pumped into vital tissues.  Hypovolemic shock occurs when there is not enough blood volume. Outline: Chapter 5: The Respiratory System The Respiratory Tract: The nose provides the openings for air to enter the inside of an animal. The nostril then opens into the nasal cavity, which divides by many scroll-like sheets of bone. Epithelium lines the bone; Mucus covers and protects the epithelial linings. **An animal sneezes when trying to clear the particles that are irritating the lining of the nose. ** Pharynx: The common area shared by the nose and the mouth, which is divided by a soft plate.  Food being swallowed passes through the Pharynx  Air breathed in threw the nose passes through the pharynx. Palpated: to be felt Endotracheal Tube: Tube; often used in administering anesthesia, hat is passed through the trachea. Mechanisms of breathing: Breathing allows air to be exchanged between the animal and the environment. Inspiration: in which air is taken into the lungs  The diaphragm contracts Expiration: in which air is forced out of the lungs.  The diaphragm relaxes. Clinical Practice: Cyanosis: a blue color associated with lox oxygen levels in the blood. Pneumonia: Inflammation of the lungs. Pleural Friction rub: Noise heard when listening to lungs with irritated pleura. Roaring: A condition in horses in which one of the vocal folds fail to open, thus causing an ensuing roaring noise when the horse breathes heavily during exertion. Heaves: Noncontagious condition in horses that causes coughing, nasal discharge, labored breathing, and rapid fatigue; often caused by inhaling dust and molds. Bronchodilators: Medications that open the airways. Outline Chapter 6: The Renal System: System Structures: Kidneys: Produce urine Ureter: Tubular structure that carries urine to the bladder. Urinary Bladder: Hollow organ that expands to store urine. Urethra: Carries urine to the outside of the body. Renal System Functions: To excrete nitrogen-containing wastes from the body. Liver- Converts ammonia into urea o Ammonia + Co2 = Urea Kidneys- Regulate water balance in the body o Regulate sodium, potassium and chloride in the blood stream. Kidney Structures and Urine Formation and Regulation: Kidney structureo Outer cortex Consists of microscopic Nephrons o Medulla o Innermost renal pelvis Urine and Blood Evaluation: Veterinarians can evaluate urine (Urinalysis) as a guide to assessing many aspects of the heath of an animal. o Urine should always be yellow in color and transparent. Ways to evaluate urine: o Refractometer- used to measure the specific gravity o Urine strip test o Microscopic evaluation o Free catch urine sample or hypodermic needle insertion to the bladder Page 87 Outline: Chapter 12: Basic Nutrients: 6 Major Components of animal diets: o o o o o o Carbohydrates Proteins Fats Water Minerals Vitamins Supply energy and structure to the cells of the body. Not used for energy, but are utilized in many of the functions in structures of the body. Plays a key role in metabolic functions of the cell Autopsy: examination to determine causes of death; sometimes also referred to as necropsy. Polysaccharides: long chains of simple sugars. Constipation: Condition that occurs when feces is to dry and moves to slowly Flatulence: An accumulation of gas in the intestinal tract Calorie: Unit of measure that defines the energy contained within a food. Hydrolysis: Process in which water is added to a molecule to cleave it into smaller parts. Rodenticide: Poison used to control rodents such as rats and mice Free Radicals: Atoms having a single free electron, which attracts another electron from neighboring atoms. Hemolysis: Break down of red blood cells. Pg. 195 Outline: Chapter 13: Species Comparison: Animal Nutrition: The basic goal of nutrition is to meet all the needs of the animal and maintain good body weight and condition. Diet Development:  Maintenance Requirements: a resting animal in a comfortable environment.  Activity level: Draft horses, hunting dogs, Race horses; have higher nutritional need.  Environment Conditions: An animal in the cold uses more energy to produce body heat.  Animal’s stage of life: Growth, pregnancy, or even lactation increase dietary demand.  Health status: Diseases can increase metabolic needs. Feeding Methods:  Free Feeding: To have good quality feed available to the animal at all times.  Feeding Time: Controls the amount of food to eat at a given time. Resting Energy Rate: (REP)  The amount of energy required by an animal at rest in a comfortable environment 30(Body Weight in Kilograms) + 70 Maintenance Energy Requirements: (MER)  Accounts for REP plus additional units required for the normal activity of the animal. Pet Food Labels: Three basic feed types:  Moist or Canned food  Dry food  Semi- moist Canned foods: (Canned sealed)  are about 75% water  Most are more palatable digestible foods.  Should be refrigerated after opened.  More expensive Semi- Moist: (generally sealed in a foil or plastic package.)  contains about 15-35% water  The pieces are coated in a carbohydrate and treated with acid to retain moisture.  Generally contains the same ingredients as dry foods. Dry Foods: (Least expensive, packaged in paper bags or cardboard boxes)  Hard food gives abrasive action to teeth  Helps to slow the accumulation of tarter  Fat in food may oxidize lowering its nutritional value Pet food labels: Must include:  Name of product  Specify what species  Label net weight  Name and address of manufacturer  Description of use/ purpose of food  Label stage of life(Puppy, adult, active senior)  Analysis of pet food  Ingredient listing Association of American Feed Control Officials (AAFCO) standards: 1. Laboratory test the food to determine the nutrient content, then to determine what stage of life meets that amount. 2. Evaluate the sustainability of the pet food threw trials, and must be labeled on the pet food stating these trials happened. Body Condition Score: 1. Emaciated 2. Thin 3. Moderate 4. Stout 5. Obese Equine Nutrition and Fiber Digestion: Grazing: Horse grazes up to 18 hours a day, provides a regular input of small meals, delivering new nutrients into the intestinal tract through the day. Concentrates: Nonforage component of a diet consisting of grains, protein sources, vitamins, and minerals. Floated: Filing of horses teeth to prevent discomfort from the edges of molars that sharpen with age. Forage: High fiber feed such as grasses hay or silage. Cribbing: wood chewing Bolt: Quick consumption of feed Ruminant Nutrition and Fiber Digestion: Ruminant stomach  Rumen  Reticulum  Omasum  Abomasum Young ruminant stomachs function like monogastrics, living off their mother’s milk, after a few months the ruminant stomach will develop. The Rumen and Reticulum are active stomachs, which frequently contract. Healthy cattle stomachs contract 1-3 times a minute. Eructated: Belch Total Mixed Ration: (TMR) The mixing of all feed stuffs in a diet Outline Chapter 14: Principles of Infectious disease: Koch’s Postulates: 2001 fear of outbreak of Anthrax Anthrax: -Skin -Intestinal - Inhaled Koch’s Postulates: A formation of principals; to prove the cause of disease: 1. The infectious agent should be detectable in sick animals but not healthy animals. 2. It should be possible to isolate and culture the organism. 3. Organisms taken from the culture and introduced into a healthy animal should cause the same disease. 4. The same organism should be isolated from the second animal as well. Koch’s postulates still help today in understanding infectious diseases. Infectious diseases are caused by microorganisms that gain entry too.  Some are contagious Tetanus : a disease introduced into the body through a wound. Some infectious diseases can be spread through the air:  Sneezing  Coughing Infectious diseases can be spread through secretions:  Nasal discharge  Saliva  Tears  Urine  Feces Fomites : Discharge which contaminates objects.  Can be the source of infections for other animals.  EX: Sharing water bowls or feeders Arthropods : Such as insects, mites, ticks, and mosquitos all play a role in transmitting disease.  Vectors: some diseases need an arthropod to evolve. Listeriosis: is a disease caused by bacteria infecting the brain. Contaminated silage is a common source of this infection in cattle. Disease Agents: Infectious diseases four classes of agents:  Bacteria  Viruses  Fungi  Parasites Bacteria: Reproduces through cell division. (Less than 20 min.) Is affected by its surrounding air; including gases such as oxygen, nitrogen, and carbon dioxide. Anaerobes: Bacteria called aerobes required oxygen to be present in the environment to allow for growth. Clostridium Tetani : Grow only in environments lacking oxygen. Facultative Anaerobes : Grow in either type of environment. Bacteria must be able to survive in hypotonic environments (such as water) Cell wall prevents the flow of water into bacteria. 1800’s Christian Gram a Danish bacteriologist developed a staining technique for bacteria in which the sample is first treated with crystal violet, a purple dye.  The sample is then treated with alcohol and acetone, to remove any free crystal violet.  The last step is to use a different colored stain, such as a pink stain. Some bacteria have a slim layer or capsule surrounding the cell wall. Some bacteria are mobile with the help of a flagella. Plasmids: Small fragments of DNA found in bacteria. Resistance to antibiotics is a very serious concern in veterinary and human medicine. Three methods of bacteria transfer the genetic material found in plasmid: 1. Method: Conjugation 2. Method: transformation 3. Method: Transduction Signs of disease occur only after sufficient numbers of pathogens are present. If immune system and treatment are unsuccessful in clearing the infection, the animal may enter a phase of chronic illness. Viruses: Are either prokaryotic or eukaryotic, it has no cell wall, no organelles, and no enzymes capable of producing energy. Have a central core of nucleic acid, either DNA or RNA, not both. Can be specific in what type of host and what type of cell they attack. Not all viruses result in death of a cell. Anemia : Low in red blood cell count Fungi: (Singular Fungus) Have eukaryotic cells Have cell walls like plants, but don’t contain chlorophyll Can infect internal organs. Systemic: Affecting the entire body. Outline: Chapter 15: Disease Prevention Disease Prevention: Animals resistance to disease  Immunity  Nutrition A healthy animal remains resistant to most diseases Skin and mucus membranes  Prevents invasions of pathogens Normal bacteria flora  Maintains the health of the animal Pathogens must adhere to the cell before the infection begins. Stress, nutrition, medications, and other diseases influence normal bacteria. Any factor con influence stress for an animal  An animal under stress release higher levels of epinephrine and cortisol. Contributing factors of Animal stress:  Over crowding  Competition for feed  Extremes of weather  Rough handling  Noise  Transport Nutritional problems can also be considered a stress; or may have a direct effect on diminishing the immune response. Antioxidants: Oxidant-inhabiting vitamins and minerals play a key role in the animal’s immune system. Factors that increase stress of an animal also contribute to increasing exposure to pathogens. Ventilation: Describes the exchange of air from within a building to the outside. Some degree of moisture is required for organisms to survive. To help prevent diseases, fresh air from the outside needs to be brought into the building and the stale air exhausted. Tunnel Ventilation: Fans are places at the end of the barn, and all air inlets are on the opposite end. Wet Dewlap: A skin infection in the lower neck of rabbits. Vaccines: Properly vaccinated animals can still become ill when overwhelmed with exposure to pathogens. Some vaccines only provide short lived immunity. Companion animals, vaccination programs are established with the goal of preventing the disease in every animal vaccinated. In the farm settings, vaccination programs help to establish heard immunity.  To establish herd immunity, the vaccination program is established to attempt to prevent a complete herd outbreak. Timing of vaccinations is key to success Immunity can be passive and active. Nemours factors can lead to a failure of a vaccination program. Biosecurity: Practices that protect the health of an animal on a farm by preventing the spread of pathogens. Outline Chapter 16: Classification of diseases: Disease in Clinical Practices: Classes of disease:  M- Metabolic  A- Anomalies (Birth defects)  D- Degenerative  T- Trauma Toxins  I- Infectious Immune Iatrogenic Idiopathic  N- Neoplasm Nutrition By considering each class of disease a veterinarian during a physical examination they may be able to understand what disease the animal has. Metabolism: describes all the processes occurring within the animal. Metabolic: disease occurring when there is a disruption in the natural process. Anomalies: can be detected at young age.  Some can result in abortions and still birth. Degenerative: often associated with aging.  Occurs with wear and tear of the body over the years. Ex: Arthritis: a disease condition in which the smooth lining of cartilage becomes rough and irregular. Trauma and Toxins: easily diagnosed drawing attention to the affected area. Iatrogenic: Conditions that occur in the result of a treatment. Ex: chronic allergies. Idiopathic: Describes the condition in which current medical knowledge cannot explain the underlying cause. Neoplasm: or a tumor developed with the growth of cells in an uncontrolled manner. (benign and malignant) Nutritional Diseases: often overlap metabolic diseases. Outline: Chapter 18: Diagnosis of Disease Disease Diagnosis: Major methods used to diagnose disease:  History of the animal  Reason for the visit (to the vet)  Physical examination  General observation and appearance  Vitals (temperature, pulse, respiration rate)  Cardiovascular system  Respiratory system  Digestive system  Musculoskeletal system  Nervous system  Skin and hair coat  Mammary system  Lymphatic System  Urinary System  Reproductive system Stethoscope may be used to listen to the heart sounds as well as the sounds in the gastrointestinal tract. Borborygmi: (singular is Borborygmus) describes heart sounds as well as the sounds in the gastrointestinal tract. Rectal examination:  Evaluates size and shape of prostate gland in male dogs  Body structure of pelvis  Character of feces within the colon Nervous and musculoskeletal system:  Observation of animal  Movement of animal  Animals reaction to its surroundings  Examination of eyes Visual Examination:  Musclskeletal problems seen and felt  Lameness of a limb Ophthalmoscope: Is the instrument used to observe the structures of the interior of the eye. Lymphatic System:  Examined by palpating lymph nodes under the skin. Mammary System:  Evaluated for swelling or heat  Milk exanimated for abnormal secretion Packed cell volume: Complete blood cell count Chemistry Panel: test that often evaluates blood sugar, electrolytes, protein, liver and pancreatic enzymes, bilirubin, and nitrogen- containing wastes. Complete blood cell count: (CBC) requires a larger volume of blood. Evaluates red blood cells (RBC) count. Numerous individual tests can be run on blood. The protein levels in blood may also be evaluated when an animal is dehydrated. Radiographs provide valuable information because the x-ray penetrates tissues of different densities at different levels. Biopsies sent to a laboratory are also commonly used techniques for submission of tissue samples:  The purpose is to determine the type of tumor, and if normal tissue is present in the specimen.  Determining the type of tumor helps to decide the treatment type.  Benign means no tumor cells are present. Pathologists must have a significant knowledge of cells and tissues. Serology: Measures the presence of antibodies against a specific organism. Ultrasound technology has become much more economical and is available at many specialist and veterinary practices.  Ultrasound image or ultrasoundogrophy utilizes very high frequency sound waves which are transmitted into the body. Outline Chapter 19: Principles of Surgery: Principles of Surgery: Skin and mucus membranes provide a barrier to invading pathogens.  Surgery disrupts this barrier and provides a site for bacteria to invade. Special care must be taken to minimize exposure of bacteria to the patient. Aseptic Technique: Describes the general practices used to minimize the risk of infection that may occur following surgery. Disinfectants: are used to thoroughly clean facilities within the operating room. Sterilization: is a procedure in which all microorganisms are destroyed. Autoclave: Is used to sterilize instruments with pressurized steam. A collection of surgical instruments necessary for a given procedure is often put together in a pack.  Good quality instruments are made of stainless steel. Commonly used Instruments:  Scalpel  Needle holder  Scissors  Tissue forceps  Hemostatic forceps  Retractors  Towel forceps or towel clamps  Spay hook Surgical Contamination: (surgeon scrub)  Head covers and surgical masks  Wash hands with a scrub brush (hands held higher than elbows)  Surgical gown  Surgical gloves Animal surgery prep:  Clipped (hair)  Vacuumed hair  Skin scrub  Drape Laceration Healing: Healing wound phases:  Hemostasis phase  Occurs following trauma/ incision  Inflammation phase  Blood vessels dilate bringing white blood cells to the area.  Proliferation Phase  Connective tissue cells enter the damaged area and formed connective tissue. Granulation Tissue: Combination of capillaries and connective tissue in an open wound that takes on a fleshy red appearance. First intention healing: Wound closure that occurs when repaired during the first 6 to 8 hours after trauma, when bacteria levels remain low, allowing wounds to heal. Golden Period: the time during the first 6 to 8 hours after trauma when bacterial numbers remain at a moderate level, allowing the wound to be closed. Second intention healing: wound closure occurring after the first 6 to 8 hours after trauma, when granulation tissue must first fill the gap between the skin edges and subsequently allow epithelial cells to grow. Proud Flesh: overgrowth of granulation tissue that prevents epithelial cells from growing across the wound. Hematoma: the accumulation of blood in a dead space. Seroma: accumulation of fluid in a dead space between tissues, similar to serum with small numbers of red blood cells. Abscess: an accumulation of fluid (pus) in a dead space between tissues containing bacteria, white blood cells and dead tissue. Dehiscence: Breaking of wound edges may occur along the entire length of the suture line or a smaller region. Surgical Considerations: Necrotic: (dead) regions of either organ need to be removed prior to finishing the surgery. Gastric dilation- volvulus syndrome: (GVD) a surgical emergency in large and deep chested dogs that have consumed a large meal and large volumes of water, which causes the accumulation of gas and rotation of the stomach, also called gastric torsion.