Glossary 553tem of air passageways formed by the branching of the
bronchial tubes within the lungs; the smallest bronchi-
oles terminate in clusters of alveoli (Chapter 15).
Bronchioles(BRONG-kee-ohls) The smallest of the air
passageways within the lungs (Chapter 15).
Brush border(BRUSH BORE-der) The collective name
for the microvilli of the absorptive cells of the mucosa of
the small intestine (Chapter 16).
Buffer system(BUFF-er SIS-tem) A pair of chemicals that
prevents significant changes in the pH of a body fluid
(Chapter 2).
Bulbourethral glands(BUHL-boh-yoo-REE-thruhl) The
glands on either side of the prostate gland that open into
the urethra; secrete an alkaline fluid that becomes part of
semen (Syn.—Cowper’s glands) (Chapter 20).
Bundle of His(BUN-duhl of HISS) The third part of
the cardiac conduction pathway, located in the upper
interventricular septum (Syn.—atrioventricular bundle)
(Chapter 12).
Burn(BERN) Damage caused by heat, flames, chemicals, or
electricity, especially to the skin; classified as first degree
(minor), second degree (blisters), or third degree (exten-
sive damage) (Chapter 5).
Bursa(BURR-sah) A sac of synovial fluid that decreases
friction between a tendon and a bone (Chapter 6).
Bursitis(burr-SIGH-tiss) Inflammation of a bursa (Chapter
6).—C—
Calcaneus(kal-KAY-nee-us) A short bone, the largest of
the tarsals; the heel bone (Chapter 6).
Calcitonin(KAL-si-TOH-nin) A hormone secreted by the
thyroid gland that decreases the reabsorption of calcium
from bones (Chapter 10).
Calcitriol(kal-SI-tree-awl) The active form of vitamin D
(Chapter 18).
Callus (KAL-us) Thickening of an area of epidermis
(Chapter 5).
Calorie(KAL-oh-ree) 1. Lowercase “calorie”: the amount
of heat energy needed to change the temperature of
1 gram of water 1 degree centigrade. 2. Uppercase
“Calorie”: a kilocalorie, used to indicate the energy con-
tent of foods (Chapter 17).
Calyx(KAY-liks) (Pl.—calyces) A funnel-shaped extension
of the renal pelvis that encloses the papilla of a renal
pyramid and collects urine (Chapter 18).
Canal of Schlemm(ka-NALof SHLEM) Small veins at the
junction of the cornea and iris of the eye; the site of reab-
sorption of aqueous humor into the blood (Syn.—scleral
venous sinus) (Chapter 9).
Canaliculi(KAN-a-LIK-yoo-lye) Small channels, such as
those in bone matrix that permit contact between adja-
cent osteocytes (Chapter 6).Cancer(KAN-ser) A malignant tumor or growth of cells
(Chapter 3).
Capacitation(KAH-pas-i-TAY-shun) The maturation of
sperm within the female reproductive tract; sperm
become capable of fertilization (Chapter 21).
Capillary(KAP-i-lar-ee) A blood vessel that takes blood
from an arteriole to a venule; walls are one cell in thick-
ness to permit exchanges of materials (Chapter 4).
Capsule(KAP-suhl) A gelatinous layer located outside the
cell wall of some bacteria; provides resistance to phago-
cytosis (Chapter 22).
Carbohydrate(KAR-boh-HIGH-drayt) An organic com-
pound that contains carbon, hydrogen, and oxygen;
includes sugars, starches, and cellulose (Chapter 2).
Carbonic anhydrase(kar-BAHN-ik an-HIGH-drays) The
enzyme present in red blood cells and other cells that cat-
alyzes the reaction of carbon dioxide and water to form
carbonic acid (Chapter 15).
Carboxyl group(kar-BAHK-sul) The COOH portion of a
molecule such as an amino acid (Chapter 19).
Carcinogen(kar-SIN-oh-jen) A substance that increases
the risk of developing cancer (Chapter 3).
Carcinoma (KAR-sin-OH-mah) A malignant tumor of
epithelial tissue (Chapter 5).
Cardiac cycle(KAR-dee-yak SIGH-kuhl) The sequence of
events in one heartbeat, in which simultaneous contrac-
tion of the atria is followed by simultaneous contraction
of the ventricles (Chapter 12).
Cardiac muscle(KAR-dee-yak MUSS-uhl) The muscle
tissue that forms the walls of the chambers of the heart
(Chapter 4).
Cardiac output(KAR-dee-yak OUT-put) The amount of
blood pumped by a ventricle in 1 minute; the resting
average is 5 to 6 liters/min (Chapter 12).
Cardiac reserve(KAR-dee-yak ree-ZERV) The difference
between resting cardiac output and maximum exercise
cardiac output (Chapter 12).
Carotid body (kah-RAH-tid BAH-dee) The site of
chemoreceptors in the wall of the internal carotid artery;
detect changes in blood pH and the levels of oxygen and
carbon dioxide in the blood (Chapter 9).
Carotid sinus(kah-RAH-tid SIGH-nus) The site of pres-
soreceptors in the wall of the internal carotid artery;
detect changes in blood pressure (Chapter 9).
Carpals(KAR-puhls) The eight short bones of each wrist
(Chapter 6).
Carrier(KAR-ree-yur) 1. A person who recovers from a
disease but continues to be a source of the pathogen and
may infect others (Chapter 22). 2. In genetics, a woman
with one gene for a sex-linked trait (Chapter 21).
Carrier enzyme(KAR-ree-yur EN-zime) An enzyme that
is part of a cell membrane and carries out the process of
facilitated diffusion of a specific substance (Syn.—trans-
porter) (Chapter 3).30Scanlon(p3) Glossary 8/17/06 11:08 AM Page 553