Glossary

A

Abdominopelvic cavity Caudal sub­division of the coelom created by the dia­phragm. It can be arbitrarily subdivided into the abdominal and pelvic spaces. Abduct Muscle action that pulls a body part away from the midline of the body.

Amphiarthrosis A Joint in which there is slight movement, e.g., between vertebrae. Anterior Directional term meaning ahead or before.

Anus The posterior opening of the ali­mentary canal through which passes undigested material.

Aorta Major artery that carries blood from the left ventricle.

Appendicular division Portion of the skeleton that includes the bones of the anterior limb, pectoral girdle, posterior limb, and pelvic girdle.

Artery Blood vessel that carries blood away from the heart.

Atlas First cervical vertebra modified to allow nodding motion between it and the occipital condyles of the skull.

Atria A pair of upper chambers of the heart that receive blood, the right one oxygen-poor blood from the body cir­culation and the left oxygen-rich blood from the pulmonary circulation.

Auricle Ear-like flaps attached to the atria that increase their volume some­what.

Axial division Portion of the skeleton that includes the skull, mandible, hyoid, sternum, ribs, and vertebral column.

Axis Second cervical vertebra modified to allow rotary motion between it and the atlas.

B

Bladder A sac-like structure that receives and stores fluids, e.g., bile in the gall bladder and urine in the urinary bladder.

Bolus A mass of chewed food, saliva, and enzymes produced in the oral cavity.

Brainstem The mesencephalon, pons, and medulla oblongata, collectively, where reflex centers control such activities as vomiting, breathing, heart functions, etc.

Bronchi Subdivisions of the trachea that increase the surface area of the respiratory system in the lungs.

C

Canal Usually tube-like passage with rounded or oval opening in bones through which nerves and blood vessels may pass.

Capitulum or head Proximal end of rib that articulates with demi-facets between adjacent vertebral bodies.

Caudal Directional term meaning toward the butt or tail of an animal.

Cephalic Referring to the head or anterior end of the body.

Cervix The distal portion of the uterine body that projects into the vagina.

Clitoris Erectile female sex organ, part of which is homologous with the penis. It is found in a depression in the ventral wall of the urogenital sinus.

Cochlea The spiral, snail-shell shaped fluid-filled apparatus of the inner ear containing the sense organs of hearing. Coelom Body cavity that is further divis­ible into compartments, e.g., thoracic, pericardial, abdominopelvic. The outer wall of the coelom is lined by a parietal serous membrane that is continuous with a visceral serous layer covering all organs that project into the cavity. Mesenteries are double layers of membrane that sus­pend the organs.

Colon The upper portion of the large intestine extending from the cecum to the rectum.

Condyle Smooth, rounded projection occurring at the end of articulating bones, e.g., the medial and lateral condyles of the femur.

Coronary sinus Main venous space of the heart carrying coronary venous blood to the right ventricle. It opens into the right ventricle.

Cortex The outer layer of a number of organs, e.g., the adrenal cortex, the cerebral cortex, the renal cortex, etc.

Cranial Directional term meaning toward the head of an animal.

Cremasteric pouch The internal sac derived from peritoneal tissues that sus­pends the testis within the scrotum.

Cutaneous Pertaining to the skin.

D

Demi-facet Smooth articulating surface on the body of two adjacent vertebrae where the capitulum of a rib articulates.

Diapophysis A transverse process that articulates with a rib.

Diarthrosis a Joint in which there is free movement, e.g., between the femur and os coxa.

Distal Some distance from the point of attachment or origin.

Dorsal Directional term meaning toward the back of an animal.

Dorsiflexion Bending the anterior surface of the manus toward the lower forelimb or the anterior surface of the pes toward the lower hindlimb.

E

Endocrine gland A ductless gland that secretes and/or releases chemical com­pounds (hormones) into the circulatory system. These chemicals affect target tissues throughout the body to control metabolism, secretion, growth, etc.

Epicondyle Projection above or dorsal to a condyle, e.g., lateral epicondyle of humerus. Muscles originate from these projections.

Epididymis Convoluted tubules occurring on the dorsal surface of the testis, but connected to the seminiferous tubules of the testes, where sperm maturation occurs.

Exocrine gland A ducted gland, e.g., the salivary glands that secrete saliva carried in a duct and released into the oral cavity.

Extension Muscle action causing an increase in the angle of a joint and move­ment of a distal body part away from a proximal one, e.g., extension of the forearm away from the upper arm by the Triceps brachii.

F

Facet Smooth, concave surface on lateral surface of vertebral transverse process that articulates with the tuberculum of a rib.

Facial Pertaining to the face.

False vocal cords Anterior pair of folds at the cranial end of the larynx. Not involved in sound production.

Fascia Sheet-like fibrous connective tissue that may bind skin to underlying muscles or may surround muscles and other organs of the body.

Fauces The space between the oral cavity and pharynx.

Fimbria(e) Movable finger-like projec­tions around the edge of the infundibulum that sweep the surface of the ovary, mak­ing it likely that oocytes released from the ovary will move into the oviduct.

Foramen Short, smooth, usually round or oval opening in bones through which nerves and blood vessels may pass.

Fossa A depression in an organ in which another organ may sit, e.g., the cerebellar fossa of the skull that houses the cerebel­lum of the brain.

Fossa ovalis A depression in the inter­atrial septum, best seen in the right atrial wall. It marks the position of a fetal open­ing between the right and left atrium allowing oxygenated blood returning from the placenta to be shunted into the “left heart” to be pumped to the anterior portion of the fetal body.

Frontal Section A section parallel to the horizontal plane of the body or organ.

G

Gland An organ of secretion that may be ductless (endocrine glands) or ducted (exocrine).

Glottis A slit between the true vocal cords that leads into the trachea.

Gonads Reproductive glands, e.g., the ovaries in the female producing oocytes and the testes in the male producing sperm cells. Endocrine tissue contained in these organs produces hormones af­fecting sexual function.

Gustation Term for the sense of taste.

Gyrus Convolution of the surface of the brain.

H

Hard palate The anterior roof of the oral cavity consisting of bone.

Hepatic In reference to or pertaining to the liver.

Hormone Chemical compound secreted by tissues or organs that regulate func­tions and growth in their own or other tissues and organs.

I

Incus The middle ear ossicle, one of three located in the middle ear.

Infundibulum Hood-like funnel attached to the proximal end of the oviduct that envelopes the ovary and receives oocytes as they are released from the ovary, thereby conveying them to the oviduct.

Inguinal The groin region.

Insertion Generally the more movable end of a muscle, causing movement of a body part.

L

Labial Pertaining to the lips.

Larynx The “voicebox” or “Adam's apple” a sound-producing organ whose wall is reinforced by a number of carti­lages.

Lateral Directional term meaning toward the side.

Ligament A band of fibrous connective tissue, supporting joints, extending be­tween two bones or between bones and cartilage; peritoneal folds or bands ex­tending between visceral organs or be­tween visceral organs and the body wall; fibrous remnants of fetal blood vessels, e.g., the ligamentum arteriosum.

Ligamentum arteriosum Ligamentous band between the pulmonary trunk and the aortic arch in mammals. In the fetus, it is the ductus arteriosus, a short vessel that allows most “right heart” blood to be shunted into the lower body circula­tion away from the lungs which are non­functional in the fetus.

Linea alba White line of connective tissue that extends down the midline of the belly.

Lumbar Back region between the ribs and the hips.

M

Malleus The most lateral of the ear ossicles abutting the tympanic mem­brane, located in the middle ear.

Manus The front paw or “hand.”

Meatus A passageway, e.g., the external auditory meatus leading to the eardrum or tympanic membrane.

Medial Directional term meaning toward the midline.

Mediastinum A potential space in the central part of the chest occupied by the pericardial cavity and its contents, trachea, esophagus, nerves, and blood vessels. Connective tissue occurs in the mediastinum that is important in securing these structures in this area.

Medulla The inner portion of a number of organs, e.g., the adrenal medulla, the renal medulla, etc.

Meninges Investing membranes associ­ated with the brain and spinal cord.

Mesentery Sheets or bands of membra­nous tissue that serve to hold organs in a relative position.

Midline An imaginary line that runs down the middle of the back or belly.

Mid-sagittal section A section exists that passes through the exact midline of the body or organ. There is only one of these. Myocardium Muscular wall of the heart.

N

Nares The external nares are synonymous with the nostrils that open into the nasal cavity. Internal nares open into the naso­pharynx at the anterior edge of the soft palate.

Nasal conchae or turbinates Thin, scroll­like bony shelves that greatly enlarge the surface area of the nasal cavity. The mucous membrane covering these shelves is important in maintaining proper moisture levels and temperatures in the respiratory stream.

Nephron The structural and functional unit of the kidney.

Neuron The structural and functional cell of the nervous system.

Nictitating membrane The vestigial, membranous fold of the lower medial corner of the eye.

O

Olfaction Term for the sense of smell.

Omentum Specialized mesenteries oc­curring in the abdominal cavity. The greater omentum is a double layered apron-like organ that hangs over the viscera. The lesser omentum extends between the liver and the stomach.

Optic chiasma X-shaped area of the optic neural circuit on the ventral aspect of the diencephalon. Some optic fibers pass straight through while others cross over as they course to the respective sides of the brain.

Oral cavity The mouth cavity.

Origin Generally the more stable and less movable end of a muscle.

Ossicles The three small bones in the middle ear.

Ostium tubae The opening of the infundibulum of the oviduct.

Ovary The primary reproductive organ in the female from which primary oocytes are released and in which impor­tant hormones controlling reproductive functions and influencing secondary sex characteristics are synthesized and secreted.

Oviduct Reproductive tube leading from the peritoneal cavity to the uterine horns. Fertilization in mammals occurs here.

Also known as uterine tubes.

P

Palate The hard palate delimits the roof of the mouth and consists of the palatine processes of the premaxilla and maxilla, as well as the palatines. The soft palate extends from the posterior rim of the hard palate.

Papilla A small cone-shaped projection.

Parietal Pertaining to a cavity wall.

Penis The erectile copulatory organ in the male that functions as an avenue to transfer sperm to the female reproductive tract and also to allow elimination of urine.

Pericardial cavity Space in which the heart lies.

Pericardium Serous membrane associated with the pericardial cavity; parietal layer lines the pericardial sac and the visceral layer covers the heart and is synonymous with the epicardium of the heart.

Peritoneal cavity That part of the celom that houses various internal organs; also known as the abdominopelvic cavity.

Peritoneum Serous membrane associated with the abdominopelvic cavity; parietal layer lines the cavity and visceral layer covers organs that project into the cavity. Pes The back paw or “foot. ”

Pharynx The space shared by the diges­tive and respiratory systems extending between the oral cavity to the esophagus and the larynx, respectively.

Plantar flexion Bending the pes away from the lower portion of the hindlimb, e.g., bringing the hindlimb up on its toes.

Pleura Serous membranes associated with the lungs; parietal layer delimits the pleural cavity and visceral layer covers the lungs that project into the pleural cavity.

Pleural cavity Subdivision of the thoracic cavity that houses the lungs.

Portal vessels Venous vessels extending between two capillary beds, e.g., the hepatic portal system.

Posterior Directional term meaning after or behind.

Postzygapophysis or posterior zygapophysis Posterior projection of neural arch of vertebra whose articulating surface points ventrally and which articulates with a prezygapophysis of the adjacent vertebra posterior to it.

Prepuce Fold of skin that envelopes the tip (glans) of the penis. Sometimes re­ferred to as the foreskin.

Prezygapophysis or anterior zygapophysis Anterior projection of neural arch of vertebra whose articulating surface points dorsally and which articulates with a postzygapophysis of the adjacent vertebra anterior to it. This arrangement permits adjacent vertebrae to support each other. Process Projection of a bone usually dis­tinct from the main body of the bone.

Pronation Muscle action that results in the palm of the hand pointing ventrally.

Protraction Muscle action that advances a body part anteriorly in a direction par­allel to the longitudinal axis, e.g., as the leg swings forward, it is protracted.

Proximal Nearest the point of attachment or origin.

Pulmonary Pertaining to the respiratory system.

Q

Quadruped An animal that walks on four legs.

R

Raphe A line of connective tissue indi­cating the Junction of two muscles, e.g., between the two halves of the mylohyoid. Rectum The terminal portion of the digestive system extending between the colon and anus.

Renal Pertaining to the kidney. Retraction Muscle action that pulls a body part posteriorly in a direction parallel to the longitudinal axis, e.g., as the leg swings backward, it is retracted. Retroperitoneal Term describing an organ that is situated beneath or behind the parietal peritoneum, e.g., the kidney, ureter.

Rugae Folds or ridges.

S

Sagittal section A section parallel to the midline of an animal or organ. There are an infinite number of sagittal sections.

Semicircular duct One of three membra­nous tubes associated with the inner ear, involved in equilibrium and body position. Sinus Irregular space in an organ, e.g., frontal sinus in the frontal bone.

Soft palate The posterior portion of the oral cavity consisting of connective tissue and muscles, appearing as a soft flap extending from the hard palate to a free edge.

Sphincter A circular, involuntary muscle that regulates openings, e.g., the anal sphincter, the pyloric sphincter, the cir­cular muscles of the iris, etc.

Stapes The most medial of the three ear ossicles that articulates with the oval window.

Sulcus Groove in the surface of the brain.

Supination Muscle action that results in the palm of the hand pointing dorsally.

Suture An immovable Joint, e.g., between skull bones.

Symphysis Type of amphiarthrotic Joint between bones, e.g., the vertebrae or the two pubes or ischia.

Synarthrosis A Joint in which there is little or no movement, e.g., between skull bones.

T

Tendon A fibrous connective tissue band extending between muscles and bones or cartilage.

Testis(es) The primary reproductive organ of the male where sperm are produced and hormones involved in controlling reproductive activities and influencing secondary sex characteristics are synthesized and secreted.

Thoracic cavity Cranial subdivision of the coelom created by the diaphragm. It is compartmentalized into the pleural and pericardial cavities.

Tonsils Masses of lymphoid tissue asso­ciated with the pharyngeal area.

Transverse or cross section A section that passes perpendicular to the longitudinal axis of the body or organ. There are an infinite number of transverse sections.

True vocal cords Pair of folds posterior to the false vocal cords at the cranial end of the larynx. Involved in sound production.

Tuberculum Smooth, concave projection distal to the capitulum of rib that articu­lates with the transverse process of a vertebra.

Tuberosity Roughened projection on the bone surface where muscles insert.

Tympanic membrane Also known as the eardrum.

U

Urogenital sinus Space in the female reproductive tract distal to the vagina where the vagina (vaginal orifice) and the urethra (urethral orifice) open. It continues to the outside where it opens by way of the urogenital aperture.

Uterine horns Enlarged distal portions of the oviduct where developing fetuses are carried.

Uterus Fused uterine horns result in the body of the uterus. During birth, kittens pass through the uterus.

V

Vagina Portion of the female reproduc­tive tract that receives the penis of the male during copulation.

Vas deferens Tube leading from the epididymis and conveying sperm to the urethra.

Vein Blood vessel that carries blood toward the heart.

Vena cava Major veins that delivers blood directly to the right atrium.

Ventral Directional term meaning toward the belly of an animal.

Ventricles Two lower chambers of the heart, the right pumping blood to the lungs and the left pumping blood to the body.

Vertebrae The series of articulated bones of the spinal or vertebral column. Vestibule An entrance space or cavity. Visceral Pertaining to the outer walls of an organ.

Z

Zygomatic arch Arch of the cheek formed by the zygomatic process of the temporal and the zygomatic process of the zygomatic or malar bones.