G-2
Glossary
Amylase
Digestive system enzyme that breaks down starchy foods.
Anabolism
(ah-nab
9
o-lizm) Energy-requiring building phase of metabo-
lism in which simpler substances are combined to form more complex
substances.
Anaerobic
(an-a
9
er-ōb-ik) Not requiring oxygen.
Anaerobic glycolysis
(gli-kol
9
ĭ-sis) Energy-yielding conversion of
glucose to lactic acid in various tissues, notably muscle, when sufficient
oxygen is not available.
Anaerobic threshold
Te point at which muscle metabolism converts to
anaerobic glycolysis.
Anaphase
Tird stage of mitosis, meiosis I, and meiosis II in which
daughter chromosomes move toward each pole of a cell.
Anastomosis
(ah-nas
0
to-mo
9
sis) A union or joining of nerves, blood
vessels, or lymphatics.
Anatomy
Study of the structure of living organisms.
Androgen
(an
9
dro-jen) A hormone such as testosterone that controls
male secondary sex characteristics.
Anemia
(ah-ne
9
me-ah) Reduced oxygen-carrying ability of blood result-
ing from too few erythrocytes or abnormal hemoglobin.
Aneurysm
(an
9
u-rizm) Blood-filled sac in an artery wall caused by dila-
tion or weakening of the wall.
Angina pectoris
(an
9
jĭ-nah pek
9
tor-is) Severe suffocating chest pain
caused by brief lack of oxygen supply to heart muscle.
Angiotensin II
(an
0
je-o-ten
9
sin) A potent vasoconstrictor activated by
renin; also triggers release of aldosterone.
Anion
(an
9
i-on) An ion carrying one or more negative charges and
therefore attracted to a positive pole.
Anoxia
(ah-nŏk
9
se-ah) Deficiency of oxygen.
Antagonist
(an-tag
9
o-nist) (1) Muscle that reverses, or opposes, the ac-
tion of another muscle. (2) Hormone that opposes the action of another
hormone.
Anterior pituitary
See
Adenohypophysis.
Antibody
A protein molecule that is released by a plasma cell (a daugh-
ter cell of an activated B lymphocyte) and that binds specifically to an
antigen; an immunoglobulin.
Anticodon
(an
0
ti-ko
9
don) Te three-base sequence complementary to
the messenger RNA (mRNA) codon.
Antidiuretic hormone
(ADH, also called vasopressin) (an
0
ti-di
0
yer-
eh
9
tik) Hormone produced by the hypothalamus and released by the
posterior pituitary; stimulates the kidneys to reabsorb more water, reduc-
ing urine volume.
Antigen (Ag)
(an
9
tĭ-jen) A substance or part of a substance (living or
nonliving) that is recognized as foreign by the immune system, activates
the immune system, and reacts with immune cells or their products.
Antigen-presenting cell (APC)
A specialized cell (dendritic cell, mac-
rophage, or B cell) that captures, processes, and presents antigens on its
surface to ± lymphocytes.
Anucleate cell
(a-nu
9
kle-āt) A cell without a nucleus.
Anus
(a
9
nus) Distal end of digestive tract; outlet of rectum.
Aorta
(a-or
9
tah) Major systemic artery; arises from the leF ventricle of
the heart.
Aortic body
Receptor in the aortic arch sensitive to changing oxygen,
carbon dioxide, and pH levels of the blood.
Apgar score
Evaluation of an infant’s physical status at 1 and 5 minutes
aFer birth by assessing five criteria: heart rate, respiration, color, muscle
tone, and reflexes.
Aerobic endurance
Te length of time a muscle can continue to con-
tract using aerobic pathways.
Aerobic respiration
Respiration in which oxygen is consumed and glu-
cose is broken down entirely; water, carbon dioxide, and large amounts
of A±P are the final products.
Afferent
(af
9
er-ent) Carrying to or toward a center.
Afferent (sensory) nerve
Nerve that contains processes of sensory neu-
rons and carries nerve impulses to the central nervous system.
Agglutination
(ah-gloo
0
tĭ-na
9
shun) Clumping of (foreign) cells; induced
by cross-linking of antigen-antibody complexes.
Agonist
(ag
9
o-nist) Muscle that bears the major responsibility for effect-
ing a particular movement; a prime mover.
AIDS
Acquired immune deficiency syndrome; caused by human im-
munodeficiency virus (HIV); symptoms include severe weight loss, night
sweats, swollen lymph nodes, opportunistic infections.
Albumin
(al-bu
9
min) Te most abundant plasma protein.
Aldosterone
(al-dos
9
ter-ōn) Hormone produced by the adrenal cortex
that regulates Na
1
reabsorption and K
1
secretion by the kidneys.
Alimentary canal
(al
0
ĭ-men
9
tar-e) Te continuous hollow tube
extending from the mouth to the anus; its walls are constructed by
the oral cavity, pharynx, esophagus, stomach, and small and large
intestines.
Alkalosis
(al
0
kah-lo
9
sis) State of abnormally low hydrogen ion concen-
tration in the extracellular fluid.
Allantois
(ah
0
lan
9
to-is) Embryonic membrane; its blood vessels develop
into blood vessels of the umbilical cord.
Alleles
Genes coding for the same trait and found at the same locus on
homologous chromosomes.
Allergy
A type of hypersensitivity (overzealous immune response to an
otherwise harmless antigen) that involves IgE antibodies and histamine
release.
Alopecia
(al
0
o-pe
9
she-ah) Baldness.
Alpha (α)-helix
Te most common type of secondary structure of the
amino acid chain in proteins; resembles the coils of a telephone cord.
Alveolar (acinar) gland
(al-ve
9
o-lar) A gland whose secretory cells form
small, flasklike sacs.
Alveolar ventilation rate (AVR)
An index of respiratory efficiency;
measures volume of fresh air that flows in and out of alveoli.
Alveolus
(al-ve
9
o-lus) (1) One of the microscopic air sacs of the lungs;
(2) tiny milk-producing glandular sac in the breast; (3) tooth socket.
Alzheimer’s disease (AD)
(altz
9
hi-merz) Degenerative brain disease re-
sulting in progressive loss of memory and motor control, and increasing
dementia.
Amino acid
(ah-me
9
no) Organic compound containing nitrogen, car-
bon, hydrogen, and oxygen; building block of protein.
Ammonia (NH
3
)
Common waste product of protein breakdown in the
body; a colorless volatile gas, very soluble in water and capable of form-
ing a weak base; a proton acceptor.
Amniocentesis
A common form of fetal testing in which a small sample
of fluid is removed from the amniotic cavity.
Amnion
(am
9
ne-on) ²etal membrane that forms a fluid-filled sac around
the embryo.
Amoeboid motion
(ah-me
9
boyd) Te flowing movement of the cyto-
plasm of a phagocyte.
Amphiarthrosis
(am
0
fe-ar-thro
9
sis) A slightly movable joint.
Ampulla
(am-pul
9
lah) A localized dilation of a canal or duct.
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