586 GlossaryTransient flora(TRAN-zee-ent FLOOR-uh) Part of nor-
mal flora; those microorganisms that may inhabit specific
sites in the body for short periods of time (Chapter 22).
Transitional(trans-ZI-shun-uhl) Changing from one form
to another (Chapter 4).
Transitional epithelium (tran-ZI-shun-uhl) A type of
epithelium in which the surface cells change from
rounded to flat as the organ changes shape (Chapter 4).
Translation(trans-LAY-shun) The process by which pro-
teins are synthesized on the ribosomes of a cell; tRNA
molecules line up amino acids according to the codons on
the mRNA molecule (Chapter 3).
Transporter(trans-POOR-ter) A protein that is part of a
cell membrane and necessary for the facilitated diffusion
of a substance such as glucose (Chapter 3).
Transverse section(trans-VERS SEK-shun) A plane or
cut from front to back, separating upper and lower parts
(Chapter 1).
Tricuspid valve(try-KUSS-pid VALV) The right AV valve,
which prevents backflow of blood from the right ventri-
cle to the right atrium when the ventricle contracts
(Chapter 12).
Trigeminal nerves(try-JEM-in-uhl) Cranial nerve pair V;
sensory for the face and teeth; motor to chewing muscles
(Chapter 8).
Triglyceride(try-GLI-si-ryde) An organic compound, a
true fat, that is made of one glycerol and three fatty acids
(Chapter 2).
Trigone(TRY-gohn) Triangular area on the floor of the
urinary bladder bounded by the openings of the two
ureters and the urethra (Chapter 18).
Triiodothyronine (T 3 ) (TRY-eye-oh-doh-THIGH-roh-
neen) A hormone secreted by the thyroid gland that
increases energy production and protein synthesis
(Chapter 10).
Trisomy(TRY-suh-mee) In genetics, having three homol-
ogous chromosomes instead of the usual two (Chap-
ter 20).
Trochlear nerves(TROK-lee-ur) Cranial nerve pair IV;
motor to an extrinsic muscle of the eye (Chapter 8).
Trophoblast(TROH-foh-blast) The outermost layer of
the embryonic blastocyst; will become the chorion, one
of the embryonic membranes (Chapter 21).
Tropomyosin(TROH-poh-MYE-oh-sin) A protein that
inhibits the contraction of sarcomeres in a muscle fiber
(Chapter 7).
Troponin(TROH-poh-nin) A protein that inhibits the
contraction of the sarcomeres in a muscle fiber (Chap-
ter 7).
True fat(TROO FAT) An organic compound in the lipid
group that is made of glycerol and fatty acids (Chapter 2).
Trypsin(TRIP-sin) A digestive enzyme that breaks down
proteins into polypeptides; secreted by the pancreas
(Chapter 16).
Tubal ligation(TOO-buhl lye-GAY-shun) A surgical pro-cedure to remove or sever the fallopian tubes; usually
done as a method of contraception in women (Chap-
ter 20).
Tubular reabsorption (TOO-byoo-ler REE-ab-SORP-
shun) The processes by which useful substances in the
renal filtrate are returned to the blood in the peritubular
capillaries (Chapter 18).
Tubular secretion(TOO-byoo-ler se-KREE-shun) The
processes by which cells of the renal tubules secrete sub-
stances into the renal filtrate to be excreted in urine
(Chapter 18).
Tunica(TOO-ni-kah) A layer or coat, as in the wall of an
artery (Chapter 13).
Tympanic membrane(tim-PAN-ik) The eardrum, the
membrane that is stretched across the end of the ear
canal; vibrates when sound waves strike it (Chapter 9).
Typing and cross matching(TIGH-ping and KROSS-
match-ing) A laboratory test that determines whether or
not donated blood is compatible, with respect to the red
blood cell types (Chapter 11).āUā
Ubiquitin(yoo-BIK-wi-tin) An intracellular protein that
tags damaged proteins so that they may be destroyed by
proteasomes (Chapter 3).
Ulna(UHL-nuh) The long bone of the forearm on the lit-
tle finger side (Chapter 6).
Ultrasound(UHL-tra-sownd) 1. Inaudible sound. 2. A tech-
nique used in diagnosis in which ultrasound waves
provide outlines of the shapes of organs or tissues (Chap-
ter 21).
Umbilical arteries(uhm-BILL-i-kull AR-tuh-rees) The
fetal blood vessels contained in the umbilical cord that
carry deoxygenated blood from the fetus to the placenta
(Chapter 13).
Umbilical cord(uhm-BILL-i-kull KORD) The structure
that connects the fetus to the placenta; contains two
umbilical arteries and one umbilical vein (Chapter 13).
Umbilical vein(uhm-BILL-i-kull VAYN) The fetal blood
vessel contained in the umbilical cord that carries oxyge-
nated blood from the placenta to the fetus (Chapter 13).
Unicellular(YOO-nee-SELL-yoo-lar) Composed of one
cell (Chapter 4).
Unsaturated fat(un-SAT-uhr-ay-ted) A true fat that is
often liquid at room temperature and of plant origin; its
fatty acids contain less than the maximum number of
hydrogens (Chapter 2).
Upper respiratory tract(UH-per RES-pi-rah-TOR-ee
TRAKT) The respiratory organs located outside the
chest cavity (Chapter 15).
Urea(yoo-REE-ah) A nitrogenous waste product formed in
the liver from the deamination of amino acids or from
ammonia (Chapter 5).
Uremia(yoo-REE-me-ah) The condition in which blood30Scanlon(p3) Glossary 8/17/06 11:08 AM Page 586