"B" Vocab for 'Anatomy and Physiology of Companion Animals'
Terms
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- B lymphocyte
- The type of lymphocyte that is responsible for humoral immunity through its transformation into a plasma cell and production of antibody.
- ball-and-socket joint
- Also called a spheroidal joint. It consists of a spherical joint surface (the ball) that fits into a closely matching concave joint surface (the socket). The shoulder and hip joints are ball-and-socket joints. Ball-and-socket joints allow the greatest range of joint movements.
- barbs
- Slender prjections off the main feather shaft that comprise a vane on each side of the shaft.
- barbules
- Microscopic projections off feather barbs that help maintain a contour feather's structure.
- basal bodies
- Refers to a pair of tubular structures. Each one is compsed of nine microtubules surrounding another pair of microtubules. Basal bodies act as teh base of cilia and flagella.
- basal cell tumors
- Tumors of the stratum germinativum or basal layer of the epithelium. They tend not to metastasize and are most common in cats.
- basal cells
- Cells located in the deepest layer of the epidermis that eventually mature to become keratinocytes.
- basal surface
- The side of an epithelial cell that faces a lower level of connective tissue.
- basement membrane
- A noncellular, collagen-based structure that supports epithelial tissue.
- basopenia
- Theoretically, a decrease in the total number of basophils in peripheral blood.
- basophilia
- An increase in the total number of basophils in peripheral blood.
- basophils
- One of the granulocytic white blood cells characterized by the presence of numerous, dark blue-staining granules in it its cytoplasm.
- belly
- The thick, central portion of a muscle.
- benign
- A nonrecurrent, nonharmful growth.
- beta1-adrenergic receptors
- Receptors associated with the sympathetic nervous system response; these receptors, when stimulated by catecholamines, tend to cause an increase in rate and force of contraction of the heart.
- beta2-adrenergic receptors
- Receptors associated with the sypathetic nervous system response; these receptors, when stimulated by catecholamines, tend to cause dilation of the bronchioles (airways) and vasodilation of some blood vessels.
- beta cells
- Cells in the pancreas that produce insulin.
- beta-oxidation
- The breakdown of fatty acid chains into two carbon fragments in the mitochondria. These two carbon fragments can be nroken down further into keton bodies and acetyl-coA.
- beta pleat
- The formation of a complex protein that is composed of hydrogen bonds corresponding with the spines of polypeptide chains.
- bicarbonate
- Often referred to as sodium bicarbonate, it acts as a bugger in the secretions (pancreas, saliva) to reduce the acidity of the stomach or rumen; also helps to buffer the pH in the blood.
- bifurcation of the trachea
- The division of the trachea at its caudal end into the left and right main bronchi, which enter the lungs.
- bilateral symmetry
- The concept that the left and right halves of an animla's body are mirror images of each other. Paired structures, such as the kidneys, are located one on each side of the body, and single sturctures, such as the heart, are located near the median plane.
- bile acids
- Hydrophilic (water loving) molecules with a hydrophobic (water hating) end secreted by the liver into the duodenum; combine with fat droplets to make them more water soluble.
- bilirubin
- The yellow breakdown product of hemoglobin.
- biopsy
- The removal of a small sample of tissue for microscopic examination. This procedure is often but not exclusively used to determine whether a tumor is benign or malignant.
- biosynthetic
- Refers to a compound manufactured within a living thing.
- blast
- A cell in the production stage of a particular substance.
- blastic transformation
- Through this process, B lymphocytes become plasma cells that produce antibodies.
- blastocyst
- The stage of development of a zygote that is ready for implantation in the uterus. It is shaped like a tiny, hollow ball of cells with a "bump" on one side that eventually develops into the embryo.
- bloat
- The accumulation of gas within the rumen or monogastric stomach causing severe distention.
- blood feather
- A developing feather that contains blood in its shaft for growth and nourishment.
- blood-brain barrier
- The functional barrier between the capillaries in the brain and the nercous tissue itself; anatomically composed of capillary walls without the opening found in other capillaries and glial cells.
- body of the penis
- The largest portion of the penis. It contains the majority of the erectile tissue of the organ.
- body of the stomach
- The central part of the stomach between the fundus and the antrum.
- bolus (of food)
- Amount of food swallowed at one time.
- bone marrow
- The soft material that fills the spaces inside bones. Two types of bone marrow are red bone marrow, which forms blood cells, and yellow bone marrow, which consists primarily of adipose connective tissue (fat).
- bones of the cranium
- The bones of the skull that surround the brain. The externally visible bones of the cranium are the occipital bone, the interparietal bones, the parietal bones, the temporal bones, and the frontal bones. The internal (hidden) bones of the cranium are the sphenoid bone and the ethmoid bone.
- bones of the face
- The skull bones that do not surround the brain. The externally visible bones of the face are the incisive bones, the nasal bones, the maxillary bones, the lacrimal bones, the zygomatic bones, and the mandible. The internal (hidden) bones of the face are the palatine bones, the pterygoid bones, the vomer bone, and the turbinates.
- bovine spongiform encephalopathy (BSE)
- Also known as mad cow disease. This was first contracted by cows in Great Britain that had consumer the flesh of sheep thought to carry infectious prions.
- Bowman's capsule
- Part of the renal corpuscle. It consists of two layers: the inner visceral layer that lies directly on the glomerular capillaries and an outer parietal layer. It functions as a plasma filter in the process of urine formation.
- brachium
- The "upper arm". The area of the thoracic limb between the elbow and the shoulder.
- brachycephalic
- Shor-faced. Brachycephalic breeds of dogs include Boston terriers, pugs, English bulldogs, and Pekinese.
- bradycardia
- Abnormally slow heart heart.
- brain stem
- The connection between the brain and the spinal cord; composed of the medulla oblongata, the pons, and the midbrain; heavily involved in autonomic control functions related to the heart, respiration, blood vessel diameter, swallowing, and vomiting.
- broad ligaments
- Paired sheets of connective tissue that suspend the uterus from the dorsal part of the abdominal cavity and atach it to the adbominal wall. They are often subdivided into the mesovarium, which supports the ovary; the mesosalpinx, which supports the oviduct; and the mesometrium, which supports the uters.
- bronchi
- The largest air passageways in the lungs. The left and right main bronchi are formed by the bifurcation of the trachea. The main bronchi divide into smaller and smaller branches within the lungs. The branching arrangement of the bronchi is referred to as the bronchial tree.
- bronchial tree
- The air passageways in the lungs between the main bronchi and the alveoli. The branching nature of the bronchi as they form smaller and smaller air passageways resembles the branching of a tree.
- bronchioles
- Some of the smallest branches of the bronchial tree. The bronchiles subdivide down to the alveolar ducts (the smallest air passageways that lead directly to the alveolar sacs).
- bronchitis A
- A lower respiratory tract infection affecting the lining fo teh larger air passageways in the lungs. Bronchitis can be a serious disease because the inflammatory fluids and excess mucus resulting from the irritaion are difficult for the animal to cough up from down deep in the lungs.
- bronchoconstriction
- Contaction of the smooth muscle that surrounds the air passageways in the lungs. Bronchoconstriction narrows the air passageways. It can be physiological, as when a mild degree of bronchoconstriction reduces the work of moving air in and out of the lungs at rest. Bronchoconstriction also can be pathological, as when inhaled irritants cause severe bronchoconstriction that makes breathing difficult.
- bronchodilation
- Relaxation of the smooth muscle that surrounds the air passageways in the lungs. Full bronchodiation cuases the air passageways to dilate to their full, large diameters. Physiological bronchodilation ovvurs furing intense physical activity when maximum air must be moved into and out of the lungs. A class of drugs called bronchodilators can be used to help relax severe bronchoconstriction, such as might occur in an asthmalike condition.
- brood patch
- Area of thickened skin on the lower abdomen of birds where feather are plucked to transfer hear to eggs during incubation.
- brown adipose tissue
- "Brown fat" found commonly throughout the body of hibernating species and neonates. It is a specialized form of adipose tissue that releases its stored lipid reserves in the form of heat. This is accomplished becuase of the high degree of vascularization and concentration of mitochondria found in brown adipose tissue.
- brush border
- The area on the free surface of an epithelial cell that is covered with microvilli.
- buccal cavity
- Although this translates literally to "cheek cavity", the buccal cavity usually refers to the mouth or oral cavity; pronounded "BHU-kal".
- buccal surface
- The surface of the caudal part of the upper and lower arcade teeth that face the cheeks; bucco is Latin for "cheeks".
- bulb of the glans
- An enlargement in the penis of the dog and related species. It is made up of erectile tissue that slowly engorges with blood during copulation. When muscles surrounding the vagina and vulva of female clamp down on teh enlarged bulb, the male connot withdraw the penis. He typically dismounts and turns to that the two animals are tail to tail. This position is known as the "tie" and usually lasts 15 to 20 minutes, after which the animals can separate.
- bulbar conjuctiva
- The transparent membrane that covers the fron (rostral) portion of the eyeball.
- bulbourethral glands
- Male accessory reproductive glands that secrete a mucus-containing fluid just beofre ejaculation that lubricates the erthra for the passage of semen and clears it of urine. Bulbourethral glands are present in all common domestic animals except the dog.