Glossary 563tion; a sac located on the undersurface of the liver; stores
and concentrates bile (Chapter 16).
Gallstones(GAWL-stohns) Crystals formed in the gall-
bladder or bile ducts; the most common type is made of
cholesterol (Chapter 16).
Gametes(GAM-eets) The male or female reproductive
cells, sperm cells or ova, each with the haploid number of
chromosomes (Chapter 3).
Gamma globulins(GA-mah GLAH-byoo-lins) Antibodies
(Chapter 14).
Ganglion(GANG-lee-on) A group of neuron cell bodies
located outside the CNS (Chapter 8).
Ganglion neurons (GANG-lee-on NYOOR-onz) The
neurons that form the optic nerve; carry impulses from
the retina to the brain (Chapter 9).
Gastric juice(GAS-trik JOOSS) The secretion of the gas-
tric pits of the stomach; contains hydrochloric acid,
pepsin, gastrin, and mucus (Chapter 16).
Gastric pits(GAS-trik PITS) The glands of the mucosa of
the stomach; secrete gastric juice (Chapter 16).
Gastric ulcer(GAS-trik UL-ser) An erosion of the gastric
mucosa and submucosa (Chapter 16).
Gastrin(GAS-trin) A hormone secreted by the G cells of
the gastric mucosa when food enters the stomach; stimu-
lates the secretion of gastric juice (Chapter 16).
Gene(JEEN) A segment of DNA that is the genetic code
for a particular protein and is located in a definite posi-
tion on a particular chromosome (Chapter 3).
Gene expression(JEEN ek-SPRESH-un) The transcrip-
tion and translation of a DNA gene to mRNA and to a
protein that gives a cell (or organ or entire organism) a
particular characteristic (Chapter 3).
Genetic code(je-NET-ik KOHD) The DNA code for
proteins that is shared by all living things; the sequence
of bases of the DNA in the chromosomes of cells
(Chapter 2).
Genetic disease(je-NET-ik di-ZEEZ) A hereditary disor-
der that is the result of an incorrect sequence of bases in
the DNA (gene) of a particular chromosome. May be
passed to offspring (Chapter 3).
Genetic immunity (je-NET-ik im-YOO-ni-tee) The
immunity provided by the genetic makeup of a species;
reflects the inability of certain pathogens to cause disease
in certain host species (Chapter 14).
Genome(JEE-nohm) The total genetic information con-
tained in the chromosomes of a cell of a species (Chap-
ter 3).
Genotype(JEE-noh-type) The genetic makeup of an indi-
vidual; the genes that are present (Chapter 21).
Gestation(jes-TAY-shun) The length of time from con-
ception to birth; the human gestation period averages
280 days (Chapter 21).
Giantism(JIGH-an-tizm) Excessive growth of the body or
its parts; may be the result of hypersecretion of growth
hormone in childhood (Chapter 10).Gingiva(jin-JIGH-vah) The gums; the tissue that covers
the upper and lower jaws around the necks of the teeth
(Chapter 16).
Gland(GLAND) A cell or group of epithelial cells that are
specialized to secrete a substance (Chapter 4).
Glaucoma(glaw-KOH-mah) An eye disease often charac-
terized by increased intraocular pressure due to excessive
accumulation of aqueous humor; may result in optic
nerve damage and blindness (Chapter 9).
Glial cells(GLEE-al SELLS) The neuroglia of the central
nervous system (Chapter 4).
Gliding joint(GLY-ding) A diarthrosis that permits a slid-
ing movement (Chapter 6).
Globulins(GLAH-byoo-lins) Proteins that circulate in
blood plasma; alpha and beta globulins are synthesized by
the liver; gamma globulins (antibodies) are synthesized
by lymphocytes (Chapter 11).
Glomerular filtration (gloh-MER-yoo-ler fill-TRAY-
shun) The first step in the formation of urine; blood
pressure in the glomerulus forces plasma, dissolved mate-
rials, and small proteins into Bowman’s capsule; this fluid
is then called renal filtrate (Chapter 18).
Glomerular filtration rate (gloh-MER-yoo-ler fill-
TRAY-shun RAYT) The total volume of renal filtrate
that the kidneys form in 1 minute; average is 100–125
mL/minute (Chapter 18).
Glomerulus(gloh-MER-yoo-lus) A capillary network that
is enclosed by Bowman’s capsule; filtration takes place
from the glomerulus to Bowman’s capsule (from the
Latin “little ball”) (Chapter 18).
Glossopharyngeal nerves (GLAH-so-fuh-RIN-jee-uhl)
Cranial nerve pair IX; sensory for taste and cardiovascu-
lar reflexes; motor to salivary glands (Chapter 8).
Glottis(GLAH-tis) The opening between the vocal cords;
an air passageway (Chapter 15).
Glucagon(GLOO-kuh-gahn) A hormone secreted by the
pancreas that increases the blood glucose level (Chap-
ter 10).
Glucocorticoids (GLOO-koh-KOR-ti-koids) The hor-
mones secreted by the adrenal cortex that affect the
metabolism of nutrients; cortisol is the major hormone in
this group (Chapter 10).
Gluconeogenesis (GLOO-koh-nee-oh-JEN-i-sis) The
conversion of excess amino acids to simple carbohydrates
or to glucose to be used for energy production (Chap-
ter 10).
Glucose(GLOO-kos) A hexose monosaccharide that is the
primary energy source for body cells (Chapter 2).
Glycerol(GLISS-er-ol) A three-carbon molecule that is
one of the end products of the digestion of fats
(chapter 2).
Glycogen(GLY-ko-jen) A polysaccharide that is the storage
form for excess glucose in the liver and muscles
(Chapter 2).
Glycogenesis(GLY-koh-JEN-i-sis) The conversion of glu-30Scanlon(p3) Glossary 8/17/06 11:08 AM Page 563