550 GlossaryAnterior(an-TEER-ee-your) Toward the front (Syn.—
ventral) (Chapter 1).
Antibiotic(AN-ti-bye-AH-tik) A chemical medication that
stops or inhibits the growth of bacteria or fungi (Chapter
22).
Antibody(AN-ti-BAH-dee) A protein molecule produced
by plasma cells that is specific for and will bond to a par-
ticular foreign antigen (Syn.—gamma globulin, immune
globulin) (Chapter 14).
Antibody-mediated immunity (AN-ti-BAH-dee-MEE-
dee-ay-ted im-YOO-ni-tee) The mechanism of adaptive
immunity that involves antibody production and the
destruction of foreign antigens by the activities of B cells,
T cells, and macrophages (Syn.—humoral immunity)
(Chapter 14).
Antibody titer(AN-ti-BAH-dee TIGH-ter) A diagnostic
test that determines the level or amount of a particular
antibody in blood or serum (Chapter 14).
Anticodon(AN-ti-KOH-don) A triplet of bases on tRNA
that matches a codon on mRNA (Chapter 3).
Antidiuretic hormone(ADH) (AN-ti-DYE-yoo-RET-ik)
A hormone produced by the hypothalamus and stored in
the posterior pituitary gland; increases the reabsorption of
water by the kidney tubules, and in large amounts causes
vasoconstriction and is called vasopressin (Chapter 8).
Antigen(AN-ti-jen) A chemical marker that identifies cells
of a particular species or individual. May be “self ” or
“foreign.” Foreign antigens stimulate immune responses
(Chapter 2).
Antigenic(AN-ti-JEN-ik) Capable of stimulating antibody
production (Chapter 14).
Anti-inflammatory effect(AN-ti-in-FLAM-uh-tor-ee) To
lessen the process of inflammation; cortisol is the hor-
mone that has this effect (Chapter 10).
Antipyretic(AN-tigh-pye-RET-ik) A medication, such as
aspirin, that lowers a fever (Chapter 17).
Antiseptic(AN-ti-SEP-tik) A chemical that destroys bacte-
ria or inhibits their growth on a living being (Chapter 22).
Antithrombin(AN-ti-THROM-bin) A protein synthesized
by the liver that inactivates excess thrombin to prevent
abnormal clotting (Chapter 11).
Antitoxin(AN-tee-TAHK-sin) Antibodies specific for a
bacterial toxin; used in treatment of diseases such as bot-
ulism or tetanus (Chapter 7).
Anus(AY-nus) The terminal opening of the alimentary tube
for the elimination of feces; surrounded by the internal
and external anal sphincters (Chapter 16).
Aorta(ay-OR-tah) The largest artery of the body; emerges
from the left ventricle; has four parts: ascending aorta,
aortic arch, thoracic aorta, and abdominal aorta (Chap-
ter 13).
Aortic body(ay-OR-tik BAH-dee) The site of chemore-
ceptors in the wall of the aortic arch; detect changes in
blood pH and the blood levels of oxygen and carbon
dioxide (Chapter 9).Aortic semilunar valve (ay-OR-tik SEM-ee-LOO-nar
VALV) The valve at the junction of the left ventricle and
the aorta; prevents backflow of blood from the aorta to
the ventricle when the ventricle relaxes (Chapter 12).
Aortic sinus(ay-OR-tik SIGH-nus) The site of presso-
receptors in the wall of the aortic arch; detect changes in
blood pressure (Chapter 9).
Apgar score(APP-gar SKOR) A system of evaluating an
infant’s condition 1 minute after birth; includes heart
rate, respiration, muscle tone, response to stimuli, and
color (Chapter 21).
Aphasia(ah-FAY-zee-ah) Impairment or absence of the abil-
ity to communicate in speech, reading, or writing. May
involve word deafness or word blindness (Chapter 8).
Aplastic anemia(ay-PLAS-tik uh-NEE-mee-yah) Failure
of the red bone marrow resulting in decreased numbers
of red blood cells, white blood cells, and platelets; may be
a side effect of some medications (Chapter 11).
Apneustic center(ap-NEW-stik SEN-ter) The respiratory
center in the pons that prolongs inhalation (Chapter 15).
Apocrine gland(AP-oh-krin) The type of sweat gland
(exocrine) found primarily in the axillae and genital area;
actually a modified scent gland (Chapter 5).
Aponeurosis(A-poh-new-ROH-sis) A flat tendon (Chap-
ter 7).
Apparent(uh-PAR-ent) 1. Readily seen or visible. 2. An
infection in which the patient exhibits the symptoms of
the disease (Chapter 22).
Appendicitis(uh-PEN-di-SIGH-tis) Inflammation of the
appendix (Chapter 16).
Appendicular skeleton(AP-en-DIK-yoo-lar) The portion
of the skeleton that consists of the shoulder and pelvic
girdles and the bones of the arms and legs (Chapter 6).
Appendix (uh-PEN-diks) A small tubular organ that
extends from the cecum; has no known function for peo-
ple and is considered a vestigial organ (Chapter 16).
Aqueous(AY-kwee-us) Pertaining to water; used especially
to refer to solutions (Chapter 2).
Aqueous humor(AY-kwee-us HYOO-mer) The tissue
fluid of the eye within the anterior cavity of the eyeball;
nourishes the lens and cornea (Chapter 9).
Arachnoid membrane(uh-RAK-noid) The middle layer of
the meninges, made of web-like connective tissue (from
the Greek “spider-like”) (Chapter 8).
Arachnoid villi(uh-RAK-noid VILL-eye) Projections of
the cranial arachnoid membrane into the cranial venous
sinuses, through which cerebrospinal fluid is reabsorbed
back into the blood (Chapter 8).
Areolar connective tissue(uh-REE-oh-lar) A tissue that
consists of tissue fluid, fibroblasts, collagen and elastin
fibers, and wandering WBCs; found in all mucous mem-
branes and in subcutaneous tissue (Syn.—loose connec-
tive tissue) (Chapter 4).
Arrhythmia(uh-RITH-me-yah) An abnormal or irregular
rhythm of the heart (Chapter 12).30Scanlon(p3) Glossary 8/17/06 11:08 AM Page 550