Glossary 603
T
T cells see T lymphocytes
T lymphocytes group of white blood cells that are part
of the immune system; complete their maturation in the
thymus before moving into the blood and the rest of the
body; T cells
tachycardia (TAK-i-KAHR-dee-a) a normal rhythm, but
with a rate above 100 bpm
talus (TAY-lus) second largest of the tarsal bones of the
ankle (next to the calcaneus)
tanning the result of exposure to sunlight and the
production of melanin
tarsal glands (TAR-sal) secretors of an oily substance;
located in the eyelids
tarsals (TAR-salz) bones of the ankle
tartar hardened plaque
tastants (TAYS-tehnts) compounds that stimulate the
gustatory hairs to send nerve impulses to the brain
taste buds sensory receptors for taste
taste pores very small openings in the top of the taste
buds through which gustatory hairs project
tectorial membrane (tek-TOR-ee-al) a gelatinous
covering over the surface of the organ of Corti
temporal bone (TEHM-poh-ral) bone that surrounds the
ear
temporal lobes (TEHM-poh-ral) the most inferior portions
of the brain; responsible for speech, hearing, vision,
memory, and emotion
tendinitis infl ammation of a tendon, usually accompanied
by pain and swelling
tendinosis degeneration of a tendon believed to be
caused by microtears in the tendon connective tissue
tendon tissue band composed of collagen and
elastic fi bers that connects a muscle to a bone
tendon sheaths double-layered synovial structures
surrounding tendons subject to friction given their
position close to bones; secrete synovial fl uid to promote
free motion of the tendons during joint movement
tensile strength the ability to withstand tension (outward
pulling force) without tearing or breaking
tension a pulling force that creates tension in the
structure to which it is applied
tertiary bronchi bronchi that arise from the secondary
bronchi and lead to the bronchioles
testes (TEHS-teez) the male sex glands
testosterone male sex hormone that is primarily
secreted by the testes in men and ovaries in women
and is responsible for the development of male sex
characteristics
tetanus a sustained, maximal level of muscle tension that
occurs with high-frequency stimulation
tetany (TET-a-nee) a condition of sustained muscular
contraction
thalamus (THAL-a-mus) the largest portion of the
diencephalon, which communicates sensory and motor
information between the body and the cerebral cortex
third-degree burns burns that destroy the entire
thickness of the skin
third-degree heart block a heart block in which the
impulse from the SA node is completely blocked
thoracic cage (thoh-RAS-ik) bony structure surrounding
the heart and lungs in the thoracic cavity; composed of
the ribs, sternum, and thoracic vertebrae
thoracic cavity (thoh-RAS-ik) the internal opening that
houses the heart and lungs
thoracic region (thoh-RAS-ik) the twelve vertebrae in the
middle of the back
thoracolumbar division (THOH-rah-koh-LUM-bar) the
sympathetic system of nerves that lies near the thoracic
and lumbar regions of the spine
thrombin (THRAHM-bin) an enzyme that combines with
the protein fi brinogen to create fi brin
thrombocytes platelets
thrombopoietin (THRAHM-boh-POY-eh-tin) a hormone
that regulates platelet production
thymosin (THIGH-muh-sin) a hormone secreted by the
thymus that is essential for the development of white
blood cells (T cells)
thymus gland a gland that secretes thymosin, a hormone
vital to the body’s immune system; functions as both an
endocrine gland and a lymphatic organ
thyroid cartilage the largest cartilaginous plate in the
larynx; Adam’s apple
thyroid gland gland located below the larynx, or
Adam’s apple, that secretes thyroid hormones (T3 and T4)
and calcitonin
thyroid hormone hormone secreted by the thyroid gland
that is responsible for the regulation of metabolism
thyroiditis (thigh-royd-IGHT-is) infl ammation of the
thyroid gland
thyroid-stimulating hormone (TSH) a tropic hormone
secreted by the anterior pituitary that acts on the
thyroid gland to release two thyroid hormones, thyroxine
and triiodothyronine
thyroxine (T4) (thigh-RAHK-seen) hormone found in
thyroid hormone that is responsible for controlling the
rate of energy metabolism and heat production
tibia (TIB-ee-a) major weight-bearing bone of the lower leg
tidal volume (TV) the amount of air inhaled in a normal
breath
tinea (TIN-ee-a) a fungal infection that tends to occur in
areas of the body that are moist
tinea corporis a fungal infection that is characterized by
a red, ring-shaped rash with a pale center; ringworm
tinea cruris a fungal infection that primarily affects males
around the groin and scrotum; jock itch
tinea pedis the most common fungal infection,
characterized by cracked, fl aky skin between the toes or
on the side of the foot; athlete’s foot
tinea unguium a fungal infection under the nails of the
fi ngers or toes; fungal nail infection
tinnitus (TIN-i-tus) a condition that causes a sound like
ringing to be heard in the ear
tissues organized groups of similar cells
tolerance reduction or elimination of the allergic
response, which may occur after immunotherapy
tonsils clusters of lymphatic tissue in the pharynx that
function as the fi rst line of defense against infection
tonsillitis (TAHN-si-LIGH-tis) infl ammation of the tonsils
torque (TORK) the rotary effect of a force
torsion (TOR-shun) a loading pattern that can cause a
structure to twist about its length
total lung capacity (TLC) a combination of the vital
capacity plus the residual volume; IRV + FRV + RV
trabecular bone (tra-BEHK-yoo-lar) interior, spongy bone
with a porous, honeycomb structure
trachea (TRAY-kee-a) the air tube that extends from the
larynx into the thorax, where it splits into the right and left
bronchi; windpipe
transcription factor a protein that controls when genes
are switched on or off