G-4 Glossaryand determines the position of that amino acid in
a polypeptide chain through complementary base
pairing with an anticodon in transfer RNA.
coenzyme (ko-en 9 z ̄ım) An organic molecule,
usually derived from a water-soluble vitamin,
that combines with and activates specific enzyme
proteins.
cofactor (ko 9 fac-tor) A substance needed for the
catalytic action of an enzyme; generally used
in reference to inorganic ions such as Ca^21
and Mg^21.
colloid osmotic (kol 9 oid oz-mot 9 ik) pressure
Osmotic pressure exerted by plasma proteins that are
present as a colloidal suspension; also called oncotic
pressure.
complement system A system of plasma proteins
that, as part of the innate immune system, can be
activated by the binding of antibodies to antigens on
the membrane of a pathogenic cell. Once activated,
different complement proteins serve to attract and
activate phagocytic cells and to form a pore that
promotes lysis of the pathogen.
compliance (kom-pli 9 ans) 1. A measure of the
ease with which a structure such as the lung expands
under pressure. 2. A measure of the change in
volume as a function of pressure changes.
conducting zone The structures and airways that
transmit inspired air into the respiratory zone of the
lungs where gas exchange occurs. The conducting
zone includes such structures as the trachea, bronchi,
and larger bronchioles.
cone Photoreceptor in the retina of the eye that
provides color vision and high visual acuity.
congestive (kon-jes 9 tiv) heart failure (CHF) The
inability of the heart to deliver an adequate blood
flow because of heart disease or hypertension. It
is associated with breathlessness, salt and water
retention, and edema.
connective tissue One of the four primary tissues,
characterized by an abundance of extracellular
material.
Conn’s syndrome Primary hyperaldosteronism in
which excessive secretion of aldosterone produces
electrolyte imbalances.
contractility (kon-trak-til 9 i-te) The ability of
cardiac muscle to contract and shorten at any
particular fiber length, independent of the preload.
Contractility is increased by epinephrine.
contralateral (kon 0 tr ̄a-lat 9 er-al) Taking place or
originating in a corresponding part on the opposite
side of the body.
cornea (kor 9 ne- ̆a) The transparent structure
forming the anterior part of the connective tissue
covering of the eye.
corpora quadrigemina (kor 9 por- ̆a kwad 0 r ̆ı-
jem 9 ̆ı-na) A region of the mesencephalon consisting
of the superior and inferior colliculi. The superior
colliculi are centers for the control of visual reflexes;
the inferior colliculi are centers for the control of
auditory reflexes.
corpus callosum (kor 9 pus k ̆a-lo 9 sum) A large
transverse tract of nerve fibers connecting the
cerebral hemispheres.
corpus (kor 9 pus) luteum (lu 9 teum) A yellowish
gland in the ovary formed from a mature graafian
follicle after it has ovulated. The corpus luteum
secretes progesterone as well as estradiol.
cortex (kor 9 teks) 1. The outer layer of an internal
organ or body structure, as of the kidney or adrenal
gland. 2. The convoluted layer of gray matter that
covers the surface of the cerebral hemispheres.
corticosteroid (kor 0 t ̆ı-ko-ster 9 oid) Any of a class
of steroid hormones of the adrenal cortex, consisting
of glucocorticoids (such as hydrocortisone) and
mineralocorticoids (such as aldosterone).cholecystokinin (ko 0 l ̆ı-sis 0 to-ki 9 nin) (CCK)
A hormone secreted by the duodenum that acts
to stimulate contraction of the gallbladder and to
promote the secretion of pancreatic juice.
cholesterol (k ̆o-les 9 ter-ol) A twenty-seven-carbon
steroid that serves as the precursor for steroid
hormones.
cholinergic (ko 0 l ̆ı-ner 9 jik) Denoting nerve
endings that, when stimulated, release acetylcholine
as a neurotransmitter, such as those of the
parasympathetic system.
chondrocyte (kon 9 dro-s ̄ıt) A cartilage-forming
cell.
chorea (k ̆o-re 9 ̆a) The occurrence of a wide variety
of rapid, complex, jerky movements that appear
to be well coordinated but that are performed
involuntarily.
chorionic gonadotropin (ko-re-on 9 ik go 9 nad-o-
tro 9 pin) (hCG) A hormone secreted by trophoblast
cells of the placenta. It activates LH receptors in the
corpus luteum of the mother’s ovaries to maintain the
corpus luteum for the first ten weeks of pregnancy.
chorionic somatomammotropin (ko-re-on 9 ik
so 9 ma-to-mam 9 o-tro-pin) (hCS) A hormone secreted
by the placenta. Its actions are similar to growth
hormone, stimulating metabolic processes that
help to provide nutrients for the fetus. Also called
placental lactogen (hPL).
chromatids (kro 9 m ̆a-tidz) Duplicated
chromosomes, joined together at the centromere, that
separate during cell division.
chromatin (kro 9 m ̆a-tin) Threadlike structures
in the cell nucleus consisting primarily of DNA
and protein. They represent the extended form of
chromosomes during interphase.
chromosome (kro 9 m ̆o-s ̄om) A structure in the cell
nucleus, containing DNA and associated proteins,
as well as RNA, that is made according to the
genetic instructions in the DNA. Chromosomes are
in a compact form during cell division; hence, they
become visible as discrete structures in the light
microscope at this time.
chylomicron (ki 0 lo-mi 9 kron) A particle of lipids
and protein secreted by the intestinal epithelial cells
into the lymph and transported by the lymphatic
system to the blood.
chyme (k ̄ım) A mixture of partially digested food
and digestive juices that passes from the pylorus of
the stomach into the duodenum.
cilia (sil 9 e- ̆a); sing., cilium. Tiny hairlike processes
extending from the cell surface that beat in a
coordinated fashion.
circadian (ser 0 k ̆a-de 9 an) rhythms Physiological
changes that repeat at approximately 24-hour
periods. They are often synchronized to changes
in the external environment, such as the day-night
cycles.
cirrhosis (s ̆ı-ro 9 sis) Liver disease characterized by
the loss of normal microscopic structure, which is
replaced by fibrosis and nodular regeneration.
clonal (kl ̄on 9 al) selection theory The theory in
immunology that active immunity is produced by
the development of clones of lymphocytes able to
respond to a particular antigen.
clone (kl ̄on) A group of cells derived from a single
parent cell by mitotic cell division. Clone formation
in lymphocytes occurs during active immunity.
CNS central nervous system That part of the
nervous system consisting of the brain and spinal
cord.
cochlea (kok 9 le- ̆a) The organ of hearing in the
inner ear where nerve impulses are generated in
response to sound waves.
codon (ko 9 don) The sequence of three nucleotide
bases in mRNA that specifies a given amino acidcardiac output The volume of blood pumped by
either the right or the left ventricle each minute.
cardiogenic (kar 0 de-o-jen 9 ik) shock Shock that
results from low cardiac output in heart disease.
carrier-mediated transport The transport of
molecules or ions across a cell membrane by means
of specific protein carriers. It includes both facilitated
diffusion and active transport.
cast An accumulation of proteins molded from the
kidney tubules that appear in urine sediment.
catabolism (k ̆a-tab 9 ̆o-liz-em) Chemical reactions in
a cell whereby larger, more complex molecules are
converted into smaller molecules.
catalyst (kata 9 - ̆a-list) A substance that increases the
rate of a chemical reaction without changing the nature
of the reaction or being changed by the reaction.
catecholamines (kat 0 ̆e-kol 9 ̆a-m ̄enz) A group of
molecules that includes epinephrine, norepinephrine,
L-dopa, and related molecules. The effects of
catecholamines are similar to those produced by
activation of the sympathetic nervous system.
cations (kat 9 i-ions) Positively charged ions, such
as sodium, potassium, calcium, and magnesium.
CatSper Unique to sperm, CatSper (cationic
channels of sperm) are Ca^21 channels that are
opened by a rise in sperm pH when the sperm are
in the female reproductive tract. The resulting entry
of Ca^21 produces hyperactivation of the sperm,
allowing more vigorous flagellar movements to more
effectively propel the sperm toward the ovum.
cell-mediated immunity Immunological defense
provided by T cell lymphocytes that come into
close proximity with their victim cells (as opposed
to humoral immunity provided by the secretion of
antibodies by plasma cells).
cellular respiration (sel 9 y ̆u-lar res 0 p ̆ı-ra 9 shun)
The energy-releasing metabolic pathways in a cell
that oxidize organic molecules such as glucose and
fatty acids, and that use oxygen as a final electron
acceptor.
centriole (sen 9 tre- ̄ol) The cell organelle that forms
the spindle apparatus during cell division.
centromere (sen 9 tr ̆o-m ̄er) The central region of
a chromosome to which the chromosomal arms are
attached.
cerebellum (ser 0 ̆e-bel 9 um) A part of the
metencephalon of the brain that serves as a major
center of control in the extrapyramidal motor system.
cerebral lateralization (ser 9 ̆e-bral lat 0 er-al- ̆ı-
za 9 shun) The specialization of function of each
cerebral hemisphere. Language ability, for example,
is lateralized to the left hemisphere in most people.
chemiosmotic (kem-e 0 os-mot 9 ik) theory The
theory that oxidative phosphorylation within
mitochondria is driven by the development of a H^1
gradient across the inner mitochondrial membrane.
chemoreceptor (ke 0 mo-re-sep 9 tor) A neural
receptor that is sensitive to chemical changes in
blood and other body fluids.
chemotaxis (ke 0 mo-tak 9 sis) The movement of an
organism or a cell, such as a leukocyte, toward a
chemical stimulus.
Cheyne-Stokes (ch ̄an 9 st ̄oks) respiration Breathing
characterized by rhythmic waxing and waning of the
depth of respiration, with regularly occurring periods
of apnea (failure to breathe).
chief cells The cells in the gastric glands that
secrete pepsinogen. Pepsinogen is an inactive
enzyme (zymogen) that is converted within the
gastric lumen to the active enzyme, pepsin. Also
called zymogenic cells.
chloride (klor 9 ̄ıd) shift The diffusion of Cl− into
red blood cells as HCO 3 − diffuses out of the cells.
This occurs in tissue capillaries as a result of the
production of carbonic acid from carbon dioxide.fox36375_glo_G1-G19.indd 4fox36375_glo_G1-G19.indd 4 2/4/15 12:29 PM2/4/15 12:29 PM