Medical Terminology Glossary
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Babinski sign - extension of the great toe, with or without fanning of the other toes, in response to stimulation of the outer margin of the sole of the foot; normal up to 1 1/2 years of age
Bainbridge reflex - the increased heart rate that follows increased pressure or distension of the right atrium
barium swallow - an X-ray examination of the upper gastrointestinal tract to evaluate for ulcers, tumors, & bleeding
baroreceptor - nerve cell capable of responding to changes in blood pressure; also called a pressoreceptor
basal metabolic rate - the rate of metabolism measured under standard or basal conditions
basilar membrane - a membrane in the cochlea of the inner ear that separates the cochlear duct from the scala tympani and on which the spiral organ (organ of Corti) rests
basophil - a type of white blood cell characterized by a pale nucleus and large granules that stain readily with basic dyes
benign - not malignant; favorable for recovery; mild disease
beta cell - a cell in the pancreatic islets (islets of Langer-hans); secretes insulin
bicuspid valve - atrioventricular (AV) valve on the left side of the heart; also called the mitral valve
bifurcate - having two branches or divisions; forked
bilateral - pertaining to two sides of the body
bile - a secretion of the liver consisting of water, bile salts, bile pigments, cholesterol, lecithin and several ions; it assumes a role in emulsification of fats prior to their digestion
biliary calculi - gallstones formed by cholesterol crystallization in bile
bilirubin - red pigment that is one of the end products of hemoglobin breakdown in liver cells; it is excreted as a waste material in the bile
bilirubinuria - presence of above-normal levels of bilirubin in urine
biliverdin - a green pigment that is one of the first products of hemoglobin breakdown in liver cells; it is converted to bilirubin or excreted as a waste material in bile
biopsy - removal of tissue or other material from the living body for examination, usually microscopic
blastocoel - the fluid-filled cavity within the blastocyst
blastocyst - in the development of an embryo, a hollow ball of cells that consists of a blastocoel (the internal cavity), trophoblast (outer cells), and inner cell mass
blastomere - one of the cells resulting from the cleavage of a fertilized ovum
blastula - an early stage in the development of a zygote
blepharism - spasm of the eyelids; continuous blinking
Bohr effect - in an acid environment, oxygen dissociates more readily from hemoglobin; hydrogen ions binding to hemoglobin alter its structure and reduce its oxygen-carrying capacity
bolus - soft, rounded mass, usually food, that is swallowed
bony labyrinth - a series of cavities within the petrous portion of the temporal bone forming the vestibule, cochlea, and semicircular canals of the inner ear
brachial plexus - a network of nerve fibers of the anterior rami of spinal nerves C5, C6, C7, C8 and T1; nerves emerging from the brachial plexus supply the upper extremity
Broca's area - motor area of the brain in the frontal lobe; translates thoughts into speech; also called the motor speech area
bronchi - branches of the respiratory passageway including primary bronchi (divisions of the trachea), secondary/ lobar bronchi (to the lobes of the lung) and tertiary/ segmental bronchi (to bronchopulmonary segments of the lung)
bronchial asthma - usually allergic reaction characterized by smooth muscle spasms in bronchi resulting in wheezing and difficult breathing
bronchiectasis - a chronic disorder in which there is a loss of normal tissue & expansion of lung air passages; characterized by difficult breathing, coughing, expectoration of pus, and foul breath
bronchiole - branch of tertiary bronchus further subdividing into terminal bronchioles (to lobules of lung), which divide into respiratory bronchioles (to alveolar sacs)
bronchitis - inflammation of bronchi characterized by hypertrophy and hyperplasia of seromucous glands and goblet cells that line the bronchi, resulting in a productive cough
bronchogenic carcinoma - cancer originating in the bronchi
bronchogram - a roentgenogram of the bronchial tree
bronchography - technique for examining the bronchial tree in which an opaque contrast medium is introduced into the trachea for distibution to the bronchial branches; produces a bronchogram
bronchopulmonary segment - one of the smaller divisions of a lobe of a lung supplied by its own branches of a bronchus
bronchoscope - an instrument used to examine the interior of the bronchi of the lungs
bronchoscopy - visual examination of the interior of the trachea and bronchi with a bronchoscope to biopsy a tumor, to clear an obstruction, to take cultures, to stop bleeding, or to deliver drugs
bronchus - one of the two large branches of the trachea
buccal - pertaining to the cheek or mouth
bulbourethral gland - one of a pair of glands located inferior to the prostate gland on either side of the urethra; it secretes an alkaline fluid into the cavernous urethra; also called a Cowper's gland
bulimia - a disorder characterized by overeating, at least twice a week, followed by purging by self-induced vomiting, strict dieting or fasting, vigorous exercise, or use of laxatives
bullae - blisters beneath or within the epidermis
bunion - lateral deviation of the great toe; produces inflammation and thickening of the bursa, bone spurs, and calluses
bursa - a sac or pouch of synovial fluid located at friction points, especially about joints
bursitis - inflammation of a bursa
buttocks - the two fleshy masses on the posterior aspect of the lower trunk, formed by the gluteal muscles