Anatomy and Physiology of Animals/Glossary/O-P

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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
Penis	Male sexual organ
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