# Anatomy and Physiology of Animals/Glossary/Book version
## A-B

| Word | Meaning |
| A | |
| Abdomen | The part of the body below the diaphragm |
| Abomasum | The final compartment of the stomach of ruminants. This the ‘true’ stomach where muscular walls churn the food and gastric juice is secreted |
| Absorption | Passage of digested food from the gut into the blood |
| Accessory gland | A gland that produces secretions that make up the liquid portion of semen |
| Acetylcholine | A neurotransmitter released at a synapse |
| Acoustic | Relating to sound |
| Active transport | The movement of substances across a membrane against the concentration gradient. Requires energy |
| Adipose tissue | Connective tissue in which the cells are filled with fat or lipid |
| Adrenal cortex | Outer portion of adrenal gland |
| Adrenal medulla | Inner portion of adrenal gland |
| Albumin | The most common of the proteins in the plasma |
| Aldosterone | The hormone produced by the adrenal cortex |
| Alimentary | Concerning nutrition |
| Alimentary canal | The long canal from the mouth to the anus through which food passes as it is digested and absorbed |
| Alkaline | Containing few hydrogen ions. pH above 7 |
| Alveolus | An air sac in the lung, where gas exchange takes place |
| Amino acids | Molecules containing nitrogen that are the building blocks of proteins |
| Amphibian | Vertebrate Class containing the frogs and toads |
| Amylases | Enzymes that split carbohydrates like starch and glycogen into monosaccharides like glucose |
| Anaemia | A condition involving a low number of red blood cells or haemoglobin in blood |
| Antagonistic muscles | A pair of muscles that work together such that as one contracts the other relaxes and vice versa. |
| Anterior | Nearer to the front of the body (usually used in human anatomy) |
| Anterior pituitary gland | Anterior portion of pituitary gland |
| Antibodies | Proteins made in response to a stimulating molecule called an antigen. The basis for the immune response |
| Anticoagulant | A substance that prevents blood clotting |
| Antidiuretic | A substance that inhibits urine production |
| Antidiuretic hormone | A hormone produced by posterior pituitary gland that stimulates water reabsorption from the kidney tubule |
| Antigens | A substance that stimulates the body to produce an antibody |
| Anus | The opening at the lower end of the rectum through which solid waste is eliminated. |
| Aorta | The main artery to body and head from heart |
| Apex | The pointed end of a cone shaped structure e.g. heart |
| Appendage | A structure attached to the body |
| Aqueous humor | The watery fluid that fills the anterior chamber of the eye |
| Arteriole | A small, almost microscopic, artery |
| Artery | A blood vessel that carries blood away from the heart |
| Articulation | The point of contact between bones. Where they move against each other |
| Appendage | A structure attached to the body |
| Aqueous humor | The watery fluid that fills the anterior chamber of the eye |
| Arteriole | A small, almost microscopic, artery |
| Artery | A blood vessel that carries blood away from the heart |
| Articulate | To move against each other - as of bones |
| Articulation | The point of contact between bones. Where they move against each other. A joint. Point of contact between 2 bones |
| Atlas | First cervical vertebra |
| Atom | A unit of matter that comprises a chemical element |
| Atrioventricular valve | A valve that prevents blood flow backwards from ventricle to atrium |
| Atrium (pl. atria) | One of two cranial chambers of heart |
| Auditory ossicle | One of 3 small bones in middle ear |
| Autonomic nervous system | The part of the vertebrate nervous system that innervates smooth and cardiac muscle and glandular tissues and governs involuntary actions. Consists of the sympathetic nervous system and the parasympathetic nervous system. |
| Axillary lymph node | A lymph node under junction of forelimb and body |
| Axis | The second cervical vertebra |
| Axon | A long extension from the neuron that carries nerve impulses away from the cell body |
| Ball and socket joint | A synovial joint where rounded end of one bone fits into cup-shaped depression of another |
| B | |
| Barb | The part of the feather that sticks out of the shaft |
| Barbules | The parts of a feather that grow out of the barbs. They have hooks and rolled edges to lock the barbs together |
| Basement membrane | The thin membrane between epidermis and dermis |
| Basophil | A white blood cell with granules in the cytoplasm |
| Biceps | The muscle that extends from the shoulder to the elbow responsible for flexing the forearm |
| Bilateral | Including both sides |
| Bile | An alkaline secretion from liver that helps break down fats into small droplets |
| Binocular vision | The placement of the eyes such that both see the same wide area but from slightly different angles |
| Binomial | The two-part Latinized name of a species, consisting of genus and species names |
| Blastocyst | A hollow ball of cells that develop from the fertilized ovum |
| Blind spot | The area of retina at end of optic nerve where there are no receptor cells |
| Blood | The fluid that circulates in the blood vessels |
| Blood pressure | The pressure of blood on the walls of the blood vessels |
| Body cavity | A space within the body that contains various organs |
| Bowman’s capsule | The double walled globe at proximal end of nephron. Encloses glomerulus |
| Brain stem | The part of the brain just above the spinal cord. Contains the medulla oblongata |
| Breed | A race or variety |
| Bronchiole | A branch of the bronchi in the respiratory system |
| Bronchus | One of the large branches of the trachea |
| Buccal | To do with the mouth |

## C-D

| Word | Meaning |
| C | |
| Callus | A thickening of the skin or growth of new bone tissue in and around a fracture |
| Canines | The long, cone-shaped teeth just behind the incisors |
| Carbohydrate | An organic compound containing carbon, hydrogen and oxygen. Made up of sugar subunits |
| Cardiac cycle | A complete heartbeat consisting of systole and diastole |
| Cardiac muscle | The muscle that makes up the wall of the heart. Striated branched fibres |
| Cardiovascular system | The body system comprising the heart, blood vessels and blood |
| Carnassial teeth | The modified premolars and molars in carnivores that slice against each other like scissors for shearing flesh and bone. |
| Carotid artery | The artery from aorta that supplies the head and brain |
| Carpal | A bone of the “wrist” |
| Cartilage | Dense connective tissue found at ends of long bones, in trachea, ear pinna. Also forms the skeleton of the foetus |
| Cataract | A condition in which the lens becomes cloudy resulting in blurred vision. |
| Caudal | Nearer to the tail than |
| Caudal vena cava | The large vein that collects blood from the body caudal to the heart |
| Cell | The basic structural and functional unit of all organisms |
| Cell division | The process by which a cell reproduces itself. Two types: mitosis and meiosis |
| Cell inclusion | A substance produced by cell that is free in cytoplasm i.e. not enclosed by a membrane |
| Cellular respiration | The chemical pathway that produces energy in the cell It consumes a fuel, generally glucose, in the presence of oxygen |
| Central nervous system | The part of the nervous system consisting of the brain and spinal cord |
| Cephalic | To do with the head |
| Cerebellum | The part of the vertebrate hindbrain located dorsally; functions in unconscious coordination of movement and balance |
| Cerebral cortex | The surface of the cerebrum; the largest and most complex part of the mammalian brain, containing sensory and motor nerve cell bodies of the cerebrum |
| Cerebrospinal fluid | The fluid that circulates around and within brain and spinal cord |
| Cerebrum | The dorsal portion of the brain composed of right and left hemispheres; the integrating center for memory, learning, emotions |
| Cervical vertebrae | The neck vertebrae |
| Cervix | The neck of the uterus |
| Chemoreceptor | A receptor that detects chemicals |
| Chorionic gonadotrophin | The hormone secreted by the placenta that prevents uterine contractions before labour and prepares the mammary glands for lactation |
| Choroid | The middle coat of the eyeball |
| Chromosome | One of the small dark staining bodies in the cell nucleus. Contains the DNA |
| Chyle | The milky fluid found in the lacteals of the small intestine |
| Chyme | The semi fluid mixture of partly digested food and digestive secretions in the stomach and small intestine |
| Cilium (pl. cilia) | A hair like process projecting from a cell. Used to move cell substances along the surface of the cell |
| Class | The taxonomic grouping of related, similar orders; category above order and below phylum |
| Clavicle | The collar bone |
| Clot | The process that changes liquid blood to a gelatinous mass |
| Coagulation | The process by which blood clots |
| Coccyx | The tail bones |
| Coccygeal vertebrae | The vertebrae of the tail |
| Cochlea | The coiled tube forming the portion of the inner ear that converts sound waves to nerve impulses |
| Collagen | A protein that is the main organic constituent of connective tissue |
| Colon | Part of the large intestine. |
| Colostrum | The first milk, it contains antibodies. |
| Common bile duct | The duct that carries both bile and pancreatic juice into the small intestine |
| Compact bone | Dense bone made up of Haversian systems |
| Conditioned Reflex | The response that is elicited by a stimulus after training has taken place |
| Condyle | A rounded protuberance at the ends of some bones where it forms an articulation with another bone |
| Cone | A light sensitive receptor in the retina that responds to colour |
| Congenital | Present at the time of birth |
| Conjunctiva | The delicate membrane covering the cornea of the eye |
| Connective tissue | One of the 4 basic tissue types of the body. Binds and supports. Consists of cells and fibres in a matrixs |
| Constipation | Decreased defecation due to decreased mobility of the intestines |
| Continuous breeding | When breeding continues throughout the year |
| Cornea | The transparent anterior layer of the eye through which the iris can be seen |
| Coronary artery | The artery that supplies the heart muscle |
| Corpus luteum | A yellow endocrine gland formed in the empty ovarian follicle after ovulation |
| Cortex | The outer layer of an organ |
| Costal | To do with a rib |
| Cowper’s gland | One of the accessory glands of the male reproductive system |
| Cranial | Towards the head |
| Cranial nerve | One of the 12 nerves that leave the brain |
| Cranium | The brain case that surrounds and protects the brain |
| Crop | The bag-like structure at the base of the oesophagus in birds.In many birds it stores food before it enters the stomachA |
| Crop-milk | Secretion produced by glands in the wall of the crop of in pigeons and doves Parents regurgitate it to feed their young |
| Cross section | Crosswise slice of an animal or organ |
| Cryptorchidism | Undescended testes |
| Cutaneous | To do with the skin |
| Cytology | The study of cells |
| Cytosol | The semi fluid portion of the cytoplasm |
| D | |
| Dehydration | Excessive loss of water from the body or its parts |
| Denaturation | Disruption of the structure of a protein by heat, acids etc. to make it inactive |
| Dendrite | A nerve cell process that carries the nerve impulses towards the cell body |
| Dental formula | The formula that describes the numbers of the different kinds of teeth |
| Dentine | The tissue below the enamel in teeth |
| Dermis | The layer of dense connective tissue lying under the epidermis |
| Diabetes insipidus | The condition caused by under secretion of antidiuretic hormone (ADH). Symptom: excretion large amounts dilute urine |
| Diabetes mellitus | The condition caused by under secretion of insulin. Symptoms: raised blood glucose levels, glucose in urine |
| Diaphragm | The dome shaped skeletal muscle separating the thoracic from the abdominal cavities |
| Diaphysis | The shaft of a long bone |
| Diarrhoea | Frequent defecation of liquid faeces |
| Diastema | The space in the jaw in animals that have no (or reduced) canines |
| Diastole | The phase of the heartbeat involving the relaxation of the ventricles |
| Diastolic blood pressure | Blood pressure in the arteries between the passage of the pulses |
| Diffusion | A passive process of movement of molecules from a region of high concentration to one of low concentration |
| Digestion | The mechanical and physical breakdown of food |
| Digitigrade locomotion | Locomotion on the “fingers” as in cats and dogs |
| Dilate | To expand or swell |
| Diploid | Having a double set of chromosomes one maternal, one paternal |
| Directional terms | Terms that describe the locations of structures in relation to other structures or locations in the body |
| Disaccharides | Double sugar, consisting of two joined monosaccharides |
| Distal | Farther away from the trunk of the body or point of origin |
| Diuretic | A chemical that reduces Antidiuretic hormone production and increases urine volume |
| Dorsal | Nearer the back of the animal than |
| Duodenum | First part of the small intestine |

## E-F

| Word | Meaning |
| E | |
| Echolocation | The use of high frequency sound like sonar and radar by animals (i.e. whales and bats) to locate objects in the surrounding environment |
| Effector | A muscle or gland that responds to a motor neuron impulse |
| Egestion | The elimination of indigestible waste products from the body |
| Electrolyte | A compound that separates into charged particles or ions |
| Electron microscope | A microscope that focuses an electron beam through a specimen, resulting in resolving power a thousandfold greater than that of a light microscope |
| Element | Any substance that cannot be broken down to any other substance |
| Embryo | The young of any organism in an early stage of development |
| Emulsification | The breakdown of large fat particles to smaller ones in the presence of bile |
| Enamel | The hard white substance covering the crown of teeth |
| Endocrine gland | A ductless gland that secretes hormones into the blood |
| Endometrium | The inner lining of the uterus |
| Endoplasmic reticulum | The network of membranous channels running through the cytoplasm of cells |
| Endothelium | The layer of squamous epithelium that lines blood vessels |
| Enzyme | A substance that increases the speed of a chemical reaction |
| Eosinophil | A white blood cell with granules in the cytoplasm |
| Epidermis | The thin outer layer of the skin |
| Epididymis | The organ composed of convoluted tubules that lies on the border of the testis Where sperm mature |
| Epiglottis | The cartilage on the top of the larynx that closes the windpipe during swallowing |
| Epiphyseal line | The remnant of epiphyseal plate at end of long bone |
| Epiphyseal plate | The cartilaginous plate at the end of a long bone where bone growth occurs |
| Epiphysis | The end of a long bone |
| Epithelial tissue | Tissue that forms outer part of skin, lines blood vessels, hollow organs and passages in the body |
| Erythrocyte | A red blood cell |
| Essential amino acids | The 10 amino acids that can not be made by animals and must be acquired in the diet |
| Eustachian tube | The passage connecting middle ear to pharynx. Equalises air pressure in middle and outer ear |
| Evolution | All the changes that have transformed life on Earth from its earliest beginnings to the diversity that characterizes it today |
| Excretion | To cast out material from the body, cell or tissue |
| Exocrine gland | A gland that secretes substances into a duct |
| Exocytosis | The discharge of substances through the plasma membrane |
| Expiration | Breathing out |
| Extension | Bending of a joint so that the angle between the bones increases |
| Extracellular fluid | Fluid outside body cells |
| F | |
| Facilitated diffusion | Diffusion across a membrane using a carrier substance |
| Fallopian tube | A slender tube through which eggs pass from an ovary to the uterus |
| Fats | Biological compounds consisting of three fatty acids linked to one glycerol molecule |
| Feedback system | The sequence of events where information about the status of a situation is continually fed back to the central control region |
| Femur | The long bone between the pelvis and the knee |
| Fertilisation | Penetration of ovum by sperm and union of nuclei |
| Fetlock | The joint between the metacarpals or metatarsals and the phalanges in horse |
| Fibrin | The insoluble protein formed from fibrinogen |
| Fibrinogen | The protein in blood plasma essential for blood clotting |
| Fibula | The lateral bone of the lower hind limb |
| Filtrate | The fluid produced by filtration of blood in the nephron |
| Flagellum | A long hair like process e.g. tail of sperm |
| Flexion | The movement involving decreasing the angle between two bones |
| Fluoroxylate | An anticoagulant used for biochemical tests for glucose |
| Foetus | Later stage of development of a young animal |
| Follicle | The cavity surrounding the developing ovum |
| Follicle stimulating hormone (FSH) | Hormone secreted by anterior pituitary gland. Stimulates development of ovarian follicle |
| Foramen | A hole in a bone for passage of vessels or nerves |
| Foramen magnum | The hole at the base of the skull for passage of the spinal cord |
| Fossa | A furrow or shallow depression in a bone |
| Fovea | The area of the retina of greatest concentration of cone cells. Area of sharpest vision |
| Functional caecum | The enlarged large intestine and caecum occupied by cellulose digesting micro-organisms |

## G-H

| Word | Meaning |
| G | |
| Gall bladder | The small pouch that stores bile |
| Gamete | A reproductive cell - sperm or ovum |
| Ganglion | A group of nerve cells outside central nervous system |
| Gas exchange | The process in which oxygen from inhaled air is transferred into the blood and carbon dioxide from the blood is transferred into the alveoli |
| Gastric juice | The digestive secretion produced by glands in the wall of the stomach |
| Gene | A biological unit of heredity |
| Gestation | The period of foetal development inside the uterus |
| Girdle | An encircling or arching arrangement of bones |
| Gizzard | The second part of the stomach of birds. In seed eating birds it contains pebbles and its muscular walls help grind the food |
| Gland | A collection of cells that secrete substances |
| Gliding joint | A synovial joint with flat articulating surfaces that permits limited movements e.g. between carpals and tarsals |
| Glomerular capsule | See Bowman’s capsule |
| Glomerulus | Tuft of capillaries surrounded by the Bowman’s capsule in nephron |
| Glottis | Vocal cords |
| Glucose | The smallest sugar. Major energy source for all cells |
| Glycerol | A molecule that combines with three fatty acid molecules to form a fat or oil |
| Glycogen | A highly branched polymer of glucose. Energy store in body |
| Goitre | A condition involving enlargement of thyroid gland |
| Golgi complex apparatus | A cell organelle concerned with packaging, processing and secretion of organic molecules |
| Gonads | The ovary and testes |
| Graafian follicle | The mature ovarian follicle |
| Grey matter | Area of the nervous system consisting of cell bodies |
| Growth hormone | A hormone secreted by the anterior pituitary gland. Stimulates growth, particularly of the skeleton |
| H | |
| Haematocrit | The percentage of blood made up of red blood cells. Also called packed cell volume (PCV) |
| Haematuria | Urine that contains red blood cells |
| Haemoglobin | Pigment containing iron in red blood cells that allows them to carry oxygen |
| Haemolysis | The escape of haemoglobin from a red blood cell |
| Haemorrhage | Bleeding |
| Haploid | Having half the normal number of chromosomes, produced by meiosis |
| Haversian canal | The canal down centre of a Haversian system |
| Haversian system | The columns of boney tissue that make up compact bone |
| Heparin | A naturally occurring anticoagulant. Also used in laboratory tests for heavy metals |
| Hepatic | To do with the liver |
| Hepatic portal vessel | The blood vessel that carries blood from the intestines to the liver |
| Hinge joint | A synovial joint that allows movement in only one plane e.g. elbow |
| Histamine | A substance secreted from white cells and platelets that is involved in the inflammatory response |
| Hock | The joint (between the tarsals and metatarsals |
| Homoiothermic | ‘Warm-blooded’ animals that regulate their body temperature |
| Hormone | A secretion from an endocrine gland |
| Humerus | The bone of the upper forearm between the scapula and the radius and ulna |
| Hyperglycemia | Elevated blood glucose level |
| Hypertension | High blood pressure |
| Hyperthermia | High body temperature |
| Hypertonic | Having an osmotic pressure higher than a solution with which it is compared |
| Hypotension | Low blood pressure |
| Hypotonic | Having an osmotic pressure lower than a solution with which it is compared |

## I-J

| Word | Meaning |
| I | |
| Ileum | The terminal part of the small intestine |
| Immunity | Being resistant to injury or invasion by microorganisms |
| Implantation | The attachment of blastocyst to lining of uterus |
| Impotence | The inability to copulate |
| Incisors | The chisel-shaped ‘biting off’ teeth at the front of the mouth |
| Induced ovulation | When ovulation is stimulated by mating as in cat and rabbit |
| Inferior | Towards the lower part of the body. Not used in animals except, perhaps, higher apes |
| Infertility | The inability to conceive or cause conception |
| Inflammation | A localised protective response to tissue injury |
| Ingestion | The taking in of food, liquids etc. |
| Inguinal | To do with the groin |
| Inorganic | Compounds that lack carbon |
| Insertion | The attachment of a muscle tendon to a bone that moves |
| Inspiration | Breathing in |
| Insulin | A hormone produced by the pancreas. Decreases blood glucose levels |
| Intercostal muscles | The muscles between the ribs. |
| Internal | Away from the surface of the body |
| Interstitial fluid | Extracellular fluid surrounding the cells |
| Intervertebral disc | A pad of cartilage between the vertebrae |
| Intestinal juice | Digestive secretion produced by glands in the lining of the small intestine |
| Intracellular fluid | Fluid within the cells |
| Invertebrates | Animals that do not posses a backbone or vertebral column |
| Ion | A charged particle |
| Isotonic | Having an osmotic pressure equal to that of a solution with which it is compared |
| J | |
| Jejunum | The middle portion of the small intestine |

## K-L

| Word | Meaning |
| K | |
| Keel | The breast bone in birds |
| Keratin | A protein found in epidermis, hair, feathers, hoofs etc. |
| Kidney | The organ that produces urine |
| L | |
| Lachrymal gland | The tear gland of the eye |
| Lactation The secretion and ejection of milk by mammary glands||
| Lacteal | A lymphatic vessel within the villi of the small intestine |
| Lacuna | A small hollow space |
| Lamellae | Concentric rings of hard calcified material found in compact bone |
| Large intestine | Part of the gut consisting of the colon, caecum, rectum and anal canal |
| Larynx | The voice box |
| Lateral | Away from the midline |
| Lens | Transparent part of the eye that helps focus light rays on the retina |
| Leukocyte | A white blood cell |
| Ligament | Dense connective tissue that attaches bone to bone |
| Lipase | Digestive enzyme that breaks down fats (lipids) |
| Lipid | Fat |
| Liver | The large organ caudal to the diaphragm |
| Longitudinal | Lengthwise slice of an animal or organ |
| Lordosis response | Standing firm to pressure on the loin region |
| Lumbar | Loin region of the back |
| Lumen | A space within an artery, vein, intestine or tube |
| Lung | The organs of respiration |
| Luteinising hormone | The hormone from the anterior pituitary gland that stimulates ovulation and development of corpus luteum |
| Lymph | Tissue fluid that has entered the lymphatic system |
| Lymph node | A structure that filters lymph and produces lymphocytes |
| Lymphatic capillary | The closed ended microscopic vessel that collects lymph in tissues |
| Lymphatic tissue | Specialised tissue that contains large numbers of lymphocytes |
| Lymphatic vessel | A large vessel that carries lymph |
| Lymphocyte | A white blood cell associated with the immune response |
| Lysosome | A cell organelle that contains digestive enzymes |

## M-N

| Word | Meaning |
| M | |
| Macrophage | A large phagocytic cell present in many tissues |
| Mammary gland | The milk producing gland |
| Mandible | The bone of the lower jaw |
| Marrow | The soft sponge like material in the cavities of bone |
| Matrix | The substance of a tissue in which the more specialised structures are embedded |
| Maxilla | The bone of the upper jaw |
| Medial | Towards the midline |
| Mediastinum | The tissue that separates the two sides of the lung |
| Medulla | Inner part of an organ |
| Medulla oblongata | The part of the brain stem or hind brain |
| Meiosis | The type of cell division for production of gametes. Halves the number of chromosomes |
| Melanin | The dark pigment in the skin and hair |
| Melatonin | The hormone produced by the pineal gland |
| Membrane | A thin, flexible sheet of tissue |
| Meninges | The membranes covering the brain and spinal cord |
| Mesentery | The membrane attaching the small intestine to the abdominal wall |
| Metacarpals | The bones of the “hand” |
| Metastasis | The distant spread of disease especially a malignant tumour from its site of origin |
| Metatarsals | The five bones of the foot that connect the “ankle” to the toes |
| Microfilaments | A solid contracting strand in the cytoplasm of cells that brings about cell contraction. |
| Microtubule | A hollow rod of protein in the cytoplasm of all eukaryotic cells and in cilia, flagella, and the cytoskeleton |
| Microvilli | The microscopic fingerlike projections from the membrane of the cells covering the villi of the small intestine |
| Middle ear | The cavity in the skull between the eardrum and inner ear housing the auditory ossicles |
| Milk teeth | The first set of teeth in a young animal |
| Minute volume | The volume of air inspired or expired during a minute of normal tidal breathing |
| Mitochondrion | The organelle in cell cytoplasm that produces energy |
| Mitosis | The cell division for growth and repair. Produces 2 cells identical to parent and each othe |
| Molars | The more posterior cheek teeth |
| Monocyte | The largest leukocyte. It is phagocytic and has no granules in the cytoplasm |
| Monosaccharide | The simplest carbohydrate. Also known as simple sugar |
| Morula | The solid mass of cells produced by successive divisions of the fertilized ovum |
| Mucus | A thick fluid secretion |
| Myelin | The fatty insulating coating to an axon of a neuron |
| N | |
| Nasal cavity | The space just inside the nostril |
| Negative feedback | Control in which the stimulus initiates actions that reverse or reduce the stimulus |
| Nephron | The functional unit of the kidney |
| Nerve | A bundle of nerve fibres |
| Nerve impulse | The nerve “current’ that passes along a neuron |
| Neuron | A nerve cell |
| Neurotransmitter | Molecules released at a synapse to transmit the nerve impulse from one neuron to the next |
| Neutral fat | A fat or triglyceride. Biological compound consisting of three fatty acids linked to one glycerol molecule |
| Neutrophil | White blood cell with granules in the cytoplasm involved in phagocytosis |
| Nictitating membrane | The third eyelid in the cat, tuatara and crocodiles |
| Normal saline | A 0.9% solution of sodium chloride |
| Nuclear membrane | The double layered membrane that surrounds the nucleus |
| Nucleolus | The spherical body within the nucleus, containing RNA |
| Nucleus | The spherical or oval body in the cell that contains the DNA |
| Nutrient | A chemical substance in food that provides energy or assists various body processes |

## O-P

| Word | Meaning |
| O | |
| Excessive accumulation of fluid in the body tissues |
| Oesophagus | The hollow muscular tube connecting the pharynx with stomach |
| The female sex hormone produced by ovaries |
| Olfactory | To do with smell |
| Omasum | Part of the modified stomach of ruminants with a folded inner surface |
| Open rooted teeth | Teeth in which the root opening remains wide. They grow continuously e.g. the incisors of rabbits and rats |
| Optic Nerve | The nerve carrying impulses from the retina of the eye to the brain |
| Orbit | The bony cavity in the skull that holds the eyeball |
| Organ | A structure with a specific function |
| Organelle | A structure in the cell with a specific function |
| Organic | A compound that contains carbon and hydrogen e.g. carbohydrates, lipids and proteins |
| Organism | A living form. One individual |
| Origin | The attachment of a muscle to a bone that does not move |
| Osmosis | The movement of water molecules across a semi permeable membrane from an area of high water concentration to an area of low water concentration |
| Osmotic pressure | The pressure required to prevent water moving across a semi permeable membrane by osmosis |
| Ossicle | A small bone |
| Ossification | The formation of bone |
| Otolith | A particle of calcium carbonate embedded in the membrane of the otolith organ of the inner ear |
| Oval window | The small opening between the middle and inner ear |
| Ovarian cycle | The series of events in the ovary associated with the maturation of the ovum |
| Ovarian follicle | The developing ovum with the epithelial tissues surrounding it |
| Ovary | The female gonad that produces ova |
| Ovulation | The release of the ovum from the mature follicle of the ovary |
| Ovum | The egg cell (plural: ova) |
| Oxyhaemoglobin | Haemoglobin combined with oxygen |
| Oxytocin | The hormone from the posterior pituitary gland. Stimulates milk “let down” |
| P | |
| Palate | The roof of the mouth |
| Palmar | The “walking” surface of the front paw |
| Pancreas | The organ lying along the caudal margin of the stomach. Has endocrine and exocrine functions |
| Pancreatic juice | The digestive secretion produced by the pancreas |
| Parasympathetic division | One of the two parts of the autonomic nervous system. Concerned with normal “at rest” activities |
| Parathyroid gland | One of four small endocrine glands on the dorsal surface of the thyroid gland |
| Parathyroid hormone | The hormone secreted from the parathyroid gland |
| Parotid gland | One of the paired salivary glands ventral to the ear |
| Parturition | The act of giving birth |
| Patella | The kneecap |
| Pathogen | A disease-producing organism |
| Pectoral | To do with the chest or breast |
| Pelvic cavity | The caudal portion of the abdominal cavity. Contains the bladder, colon and reproductive structures |
| Pelvic girdle | The bony structure formed by the hip bones, sacrum and coccygeal bones |
| Pelvis | The structure formed by the two hip bones, sacrum and coccyx |
| Pepsin | A protein digesting enzyme secreted by the stomach wall |
| Pericardial cavity | The small cavity between the two layers of the pericardial membranes |
| Pericardium | The membrane that encloses the heart |
| Periosteum | The tough connective tissue covering of a bone |
| Peripheral | Located on the outer part of the body |
| Peripheral nervous system | The part of the nervous system composed of the cranial and spinal nerves |
| Peristalsis | The successive muscular contractions along the wall of the gut |
| Peritoneum | The membrane that lines the abdominal cavity and covers the abdominal organ |
| Permanent teeth | The second set of teeth that persist through life |
| Peyer’s Patches | Large clusters of lymph nodules found in the wall of the small intestine |
| pH | A symbol that indicates the acidity or alkalinity of a solution |
| Phagocytosis | The process by which cells ingest particles and bacteria |
| Phalanges | The bones of the “fingers” and “toes” |
| Pharynx | The throat |
| Phospholipid bilayer | The arrangement of phospholipids molecules in two layers |
| Phospholipids | Molecules that make up the double layer of biological membranes |
| Photoreceptor | A receptor that detects light |
| Photosynthesis | The making of organic molecules by plants using energy from the sun |
| Physiology | The science that deals with the functions of an organism and its parts |
| Pineal gland | The gland situated in the brain that secretes melatoni |
| Pinna | The projecting part of the external ear |
| Pinocytosis | The process by which cells ingest liquid |
| Pituitary gland | The endocrine gland lying under the caudal surface of the brain attached to the hypothalamus by a stalk |
| Pivot joint | A synovial joint where a peg of bone articulates with a ring of bone as in the joint between the atlas and axis |
| Placenta | The special structure through which the exchange of materials between the foetus and mother occurs |
| Plantar | The “walking” surface of the hind paw |
| Plantigrade locomotion | Locomotion involving placing the whole surface of the foot on the ground as in humans and bears |
| Plasma | The fluid that surrounds the blood cells |
| Plasma membrane | The outer membrane surrounding the cell |
| Platelets | Cell fragments in the blood essential for clotting |
| Pleura | Membranes that cover the lungs and line the walls of the chest and diaphragm |
| Pleural cavity | The space between the two layers of the pleura |
| Plexus | A network of nerves |
| Poikilothermic | ‘Cold-blooded’ animals whose body temperature varies, to a large extent depending on the environment |
| Polysaccharides | A carbohydrate formed from up to a thousand monosaccharides |
| Preen | To clean, straighten and fluff feathers |
| Premolars | The more anterior cheek teeth |
| Progesterone | The hormone produced by the corpus luteum |
| Prolactin | A hormone produced by the anterior pituitary gland |
| Prostate gland | The gland caudal to bladder in males |
| Proteases | Enzymes that split proteins into amino acids |
| Protein | An organic compound consisting of carbon, hydrogen, oxygen and nitrogen. Made up of amino acids |
| Proximal | Nearer to the body or to the point of origin |
| Pulmonary | To do with the lungs |
| Pulp cavity | The cavity within the crown and neck of a toot |
| Pulse | The series of waves of high pressure blood passing along an artery |
| Pupil | The hole in the centre of the iris of the eye |
| Pus | Dead white blood cells |
| Pyloric sphincter | The ring of smooth muscle between the stomach and the small intestine |

## Q,R,S

| Word | Meaning |
| R | |
| Radius | The shorter bone of the forelimb between the humerus and the “wrist” |
| Receptor | A specialized cell that responds to specific sensory stimuli such as touch,pressure, light etc. |
| Red marrow | Bone marrow found in the spaces of spongy bone.Makes red blood cells |
| Reflex | A fast automatic response to a stimulus |
| Reflex arc | Consists of receptor, sensory, relay and motor neurons and effector |
| Refraction | Bending of light as it passes from one medium to another |
| Relaxin | The hormone secreted by the placenta and ovaries that eases the joint between the right and left pelvis and dilates the cervix for birth |
| Renal | To do with the kidney |
| Renal pelvis | The cavity in the centre of the kidney |
| Renal pyramid | A cone shaped structure in kidney medulla |
| Renal system | The body system involving the kidneys |
| Reticulum | The part of the modified stomach of ruminants with honeycomb of raised folds on its inner surface |
| Retina | The inner coat of the eyeball. Nerve calls here (rods and cones) respond to light ray |
| Ribosome | The organelle in the cell that makes proteins |
| Rickets | A bone disorder caused by inadequate vitamin D |
| Rod | The photoreceptor in the retina, specialized for vision in dim light |
| Rostral | Towards the muzzle |
| Rumen | The first and largest compartment of the modified stomach of ruminants.It houses the microorganisms |
| Ruminant | An animal with a rumen e.g. sheep, cow, camel |
| Rumination | Chewing the “cud” |
| S | |
| Sacrum | The triangular bone formed from fused sacral vertebrae.Located between the two hipbones |
| Sagittal plane | Plane that divides the body into left and right portions |
| Sagittal section | Lengthwise slice of an animal or organ |
| Saliva | The secretion from the salivary glands |
| Salivary amylase | The starch digesting enzyme in saliva |
| Saturated fat | A fat containing saturated fatty acids |
| Scapula | The shoulder blade |
| Sciatic nerve | The large nerve that passes down the hind leg |
| Sclera | The fibrous outer coat of eyeball |
| Seasonal breeding | Breeding confined to certain seasons of the year |
| Sebaceous gland | An exocrine gland in the dermis of the skin associated with a hair follicle |
| Sebum | The waxy secretion from a sebaceous gland |
| Secondary sex characteristic | A characteristic that develops at sexual maturity. e.g. large body size of males, manes in lions |
| Secretion | The production or release of a fluid from a gland |
| Semen | The fluid discharged at ejaculation of male. Consists of sperm and fluid |
| Semicircular canals | The membranous fluid filled canals containing receptors for equilibrium |
| Semilunar valve | The valve guarding the entrance to the aorta or the pulmonary artery |
| Seminal vesicle | A gland that secretes a component of semen |
| Seminiferous tubule | The tightly coiled duct in the testis where sperm are produced |
| Semi-permeable membrane | A membrane that allows some substances to cross more easily than others |
| Sensory neuron | A neuron that carries a nerve impulse towards the central nervous system |
| Serum | Plasma minus its clotting proteins |
| Sesamoid bones | Small bones usually found in tendons |
| Shock | Reduced cardiac output resulting in failure to deliver adequate oxygen and nutrients to the body |
| Shoulder | The synovial joint where the humerus joins the scapula |
| Sinus | An air cavity in a bone especially in the bones of the face or skull |
| Skeletal muscle | Tissue specialized for contraction with striated fibres. Attached to the bones of the skeleton |
| Skull | The skeleton of the head |
| Small intestine | The long tube of the gut that begins at the stomach and ends at the large intestine |
| Smooth muscle | Tissue specialized for contraction with spindle shaped non striated fibres |
| Soft palate | The posterior portion of the roof of the mouth |
| Solution | One or more substances dissolved in a liquid |
| Specific gravity | A measure of the density of a liquid or solid, as compared with that of water. |
| Sperm duct | The tube that carries sperm from the epididymis to the urethra. Also called the vas deferens |
| Spermatic cord | The structure in the male reproductive system attached to the testis that carries the vas deferens, arteries, veins, etc. |
| Spermatozoon | A mature sperm cell |
| Sphincter | A ring-like muscle that controls movement along a body passage or orifice |
| Spinal cord | The mass of nerve tissue in the vertebral column |
| Spinal nerve | One of the nerves that originate in the spinal cord |
| Spleen | The large lymphatic organ near the stomach that stores blood and produces lymphocytes |
| Spongy bone | The inner layer of bone; found at the ends of long bones less dense than compact bone |
| Squamous | Scale like |
| Starch | The storage polysaccharide in plants consisting of many glucose molecules |
| Sterile | Free from any living micro organisms |
| Sternum | The breastbone |
| Stifle | The joint between the femur and the tibia on the hind leg |
| Stimulus | Any change in the environment capable of initiating a nerve impulse |
| Stomach | The large baglike part of the gut between the oesophagus and the small intestine |
| Striated muscle | Striped or skeletal muscle |
| Subcutaneous | Beneath the skin |
| Submandibular gland | The salivary gland beneath the tongue |
| Substrate | A substance on which an enzyme acts |
| Sulcus | A groove or depression between the convolutions of the brain |
| Superficial | Nearer to the surface of |
| Suture | An immoveable joint in the skull |
| Sympathetic division | One of the two subdivisions of the autonomic nervous system concerned with reacting to emergency situations |
| Synapse | The junction between two neurons |
| Synovial joint | A fully moveable joint |
| System | An association of organs that have a common function, e.g. digestive system, respiratory system |
| Systemic circulation | The blood circulation from the left ventricl through the aorta to all the organs of the body and back to the heart |
| Systole | The phase of the heartbeat involving contraction of the ventricles |
| Systolic blood pressure | The blood pressure during passage of the pulse |
| Synapse | The junction between two neurons |
| Synovial joint | A fully moveable joint |

## T,U,V,W,X,Y,Z

| Word | Meaning |
| T | |
| Target cell | A cell whose activity is affected by a particular hormone |
| Tarsals | The bones of the “ankle” |
| Tendons | A tough cord of fibrous connective tissue that connects muscles to bones |
| Testis | The male gonad that produces sperm |
| Testosterone | The hormone produced by the cells between the seminiferous tubules of the testis |
| Thoracic cavity | The chest cavity that contains the heart and lungs |
| Thorax | The part of the body between the neck and the diaphragm |
| Thymus gland | The organ dorsal to the sternum that is essential to the immune response |
| Thyroid gland | The endocrine gland with lobes on either side of the trachea |
| Thyroxine | The hormone secreted by the thyroid gland |
| Tibia | The medial bone of the lower hind limb |
| Tidal breathing | Normal at rest breathing |
| Tidal volume | The volume of air breathed in or out in any one “at rest” breath |
| Tissue | A group of similar cells |
| Tissue fluid | Plasma that has left the capillaries and flowed into the spaces between the cells of the tissues; also known as intercellular fluid or interstitial fluid |
| Total lung capacity | The sum of the tidal volume, inspiratory reserve, expiratory reserve and residual volume of the lungs |
| Trachea | The windpipe |
| Transverse | A crosswise slice of an animal or organ |
| Triceps | The muscle that extends from the shoulder to the elbow responsible for extending the forearm |
| Triglycerides | A biological compound consisting of three fatty acids linked to one glycerol molecule. A fat |
| Trunk | The part of the body to which the fore and hind limbs are attached |
| Tympanic membrane | The thin transparent membrane of connective tissue between the external ear, canal and the middle ear. Also called the eardrum |
| U | |
| Ulna | The longer bone of the forelimb between the humerus and the “wrist” |
| Umbilical cord | The cord containing arteries and vein that attaches the foetus to the placenta |
| Unguligrade locomotion | Locomotion on the “fingernails” as in horses and pigs |
| Urea | The soluble excretory product produced when excess amino acids (from proteins) are broken down by the body |
| Ureter | One of two tubes that connect the kidney with the bladder |
| Urethra | The duct from the bladder to the exterior of the body |
| Uric acid | An insoluble excretory product produced when excess amino acids(from proteins) are broken down by the body |
| Urinalysis | The analysis of urine |
| Urine | The fluid produced by the kidneys |
| Uterus | The hollow muscular organ in females where the foetus develops |
| V | |
| Vagina | The muscular, tubular organ in the female where sperm are deposited during copulation |
| Vagus nerve | The cranial nerve that controls the muscles that bring about swallowing,the muscles of the heart, airways, lungs, stomach and intestines |
| Vane | The flat part of a feather emerging from the shaft; there are two vanes per feather |
| Vas deferens | The duct that conducts the sperm from the epididymis to the urethra |
| Vascular | To do with blood |
| Vasoconstriction | The decrease in size of the channel down a blood vessel |
| Vaso dilation | The increase in size of the channel down a blood vessel |
| Vein | A blood vessel that carries blood towards the heart |
| Velvet | The tissue layer that covers antlers |
| Vena cava | One of two large blood vessels that return blood to the heart |
| Ventral | Nearer the belly of the animal than |
| Ventricles | The caudal chambers of the heart |
| Venule | A small vein |
| Vertebral canal | The channel that encloses and protects the spinal cord |
| Vertebrates | Animals that have a backbone or vertebral column |
| Vesicles | Small, intracellular membrane-bound sac |
| Vestibular organ | The organ of balance – semicircular canals and otolith organ |
| Villus (pl. villi) | A projection from the lining of the small intestine to help absorb digested food molecules |
| Viscera | The organs in the abdominal and pelvic cavities |
| Visceral skeleton | Bones formed in the organs of the body |
| Viscosity | The thickness or stickiness of a liquid |
| Vital capacity | The sum of the inspiratory and expiratory reserve volumes and the tidal volume |
| Vital capacity | The volume of the air expired when a maximum expiration follows a maximum inspiration |
| Vitamin | An organic molecule necessary in minute quantities for the proper functioning of the chemical processes in the body |
| Vitreous Humor | The fluid in the posterior chamber of the eye |
| W | |
| White matter | Masses of myelinated axons located in the brain and spinal cord |
| Y | |
| Yellow marrow | Bone marrow that is yellow with fat; found at the ends of long bones |
| Z | |
| Zona pellucida | The tough layer surrounding the ovum |
| Zygote | Single cell resulting from the union of the sperm and egg |