Glossary 589
gastroesophageal refl ux (GAS-troh-eh-SAHF-a-JEE-al)
the movement of chyme from the stomach into the lower
esophagus
gastroesophageal refl ux disease (GERD) (GAS-troh-eh-
SAHF-a-JEE-al) chronic infl ammation of the esophagus
caused by the upward fl ow of gastric juice
gastrointestinal tract (GAS-troh-in-TEHS-tin-ahl) the
stomach, small intestine, and large intestine; alimentary
canal
genital herpes a sexually transmitted disease that may
cause blisters or sores in the genital or anal area or near
the mouth; may cause no symptoms
gestation the period from fertilization to birth; pregnancy
gingiva (JIN-ji-vuh) soft tissue that covers the necks of
the teeth, the mandible, and the maxilla; gum
glands epithelial cells that are organized to produce and
secrete substances
glans penis the enlarged end of the penis
glaucoma (glaw-KOH-ma) a condition of increased
pressure within the eyeball
glenohumeral joint (GLEH-noh-HYOO-mer-al) joint
between the glenoid fossa of the scapula and the
humerus; the shoulder joint
glenoid fossa (GLEE-noyd) shallow socket on the lateral
end of each scapula that forms part of the shoulder joint
glial cells (GLIGH-al) supporting cells that appear in
nerve tissue
gliding joint type of diarthrosis that allows only sliding
motion of the articulating bones
globin (GLOH-bin) the large protein present in
hemoglobin
glomerular capsule (glah-MER-yoo-lar) a thin,
membranous, double-walled capsule surrounding the
glomerulus of a nephron
glomerular capsule space the hollow space between
the inner and outer surfaces of the glomerular capsule
glomerular fi ltrate the fl uid that reaches the glomerular
capsular space
glomerular fi ltration rate (GFR) the total amount of
water fi ltered from the glomerular capillaries into the
glomerular capsule per unit of time; usually measured in
milliliters per minute
glomerulus (glah-MER-yuh-lus) a cluster of capillaries
around the end of a renal corpuscle
glossopharyngeal nerve (GLAHS-oh-feh-RIN-jee-al)
one of three cranial nerves that is responsible for
transmitting taste sensations to the brain
glottis (GLAHT-is) the opening to the larynx and trachea;
includes the vocal cords
glucagon (GLOO-kuh-gahn) hormone secreted by the
pancreas that causes the breakdown of glycogen stored
in the liver
glucocorticoids (gloo-koh-KORT-i-koids) a group of
steroid hormones produced by the adrenal cortex that
regulates carbohydrate, fat, and protein metabolism
gluconeogenesis (gloo-koh-nee-oh-JEH-neh-sis) the
process by which fats and proteins are converted into
glucose by the liver
glucose the main form of sugar that circulates in the
blood
glucose tolerance test a test in which glucose is given
and blood samples are taken afterwards to determine
how quickly blood sugar levels return to normal
glyceride (GLIS-er-ighd) compound composed of a
glycerol molecule with one, two, or three fatty acids
attached
glycocalyx (GLIGH-koh-KAY-liks) the layer of
carbohydrate groups surrounding a cell
glycogen (GLIGH-koh-jehn) a polymer of glucose that is
found in animals
glycolysis (gligh-KAHL-i-sis) the breakdown of a glucose
molecule into two pyruvate molecules
glycoproteins (GLIGH-koh-PROH-teenz) proteins with
carbohydrate groups attached
goiter (GOY-ter) an enlarged thyroid caused by
insuffi cient amounts of iodine or a thyroid disorder
Golgi apparatus (GOHL-jee) a set of membranous discs
in the cytoplasm
gonads (GOH-nads) the organs that produce gametes
(oocytes and sperm): the ovaries in females and the
testes in males
gonorrhea (GAHN-oh-REE-a) a sexually transmitted
disease that may cause pain during urination, unusual
discharge of fl uid from the vagina or penis, or no
symptoms at all; can lead to infertility
granulocytes (GRAN-yoo-loh-SIGHTS) white blood cells
whose cytoplasm contains granules
granulosa cells (GRAN-yoo-LOH-sa) the supporting
cells that surround the oocyte
Graves disease an autoimmune disorder that causes
an overactive thyroid gland and outward bulging of the
eyes
gray matter tracts of unmyelinated fi bers in the central
nervous system
greater vestibular glands mucus-secreting glands that
lie on either side of the vagina
gross anatomy the study of the body structures that can
be seen with the naked eye
growth hormone an anterior pituitary hormone that
promotes bone and muscle development
gustatory cells (GUS-ta-TOH-ree) sensory receptors
within a taste bud
gustatory hairs (GUS-ta-TOH-ree) threads that emerge
from the gustatory cells
gyrus (JIGH-rus) a curved, raised area on the brain
H
hair cells sensory receptors located in the organ of Corti
and semicircular canals
hairy tongue a symptom of certain conditions that promote
unnatural growth of the gustatory hairs of the tongue
hammer tiny bone in the middle ear that transmits sound
from the tympanic membrane (eardrum) to the anvil
haploid (HAP-loyd) having a single set of unpaired
chromosomes
hardening of the arteries see atherosclerosis
hard palate (PAL-at) the anterior part of the palate that
separates the oral and nasal cavities, which is supported
by bone
Haversian canals (ha-VER-zhen) major passageways
running in the direction of the length of long bones,
providing a path for blood vessels
Haversian system includes a single Haversian canal
along with its multiple canaliculi, which branch
out to join with lacunae, forming a comprehensive
transportation matrix for supply of nutrients and removal
of waste products; osteon
HbA1c test a glucose tolerance test that measures the
average blood glucose levels over the course of three
months
hearing aids devices that amplify and change sounds so
that the wearer can better hear them