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Glossaries - T

We've defined thousands of terms related to health care. This page discusses glossary terms with the letter T.

T Cell

white blood cell critical to the immune response. Among these are CD4+ T cells and CD8+ T cells. The "T" stands for the thymus, where T lymphocytes mature. (See also lymphocyte).


a disturbance of the heart's rhythm resulting in a heart rate of over 100 beats per minute.


Tough, fibrous cords of tissue that connect muscle to bone.

Tenesmus (tuh-NEZ-mus)

Straining to have a bowel movement. May be painful and continue for a long time without result.

TENS (transcutaneous electrical nerve stimulation)

Passes electricity to nerve cells through electrodes placed on the patient's skin. TENS is used to relieve pain.

Testes (TES-tease)

plural for testis, one of the two male reproductive glands located in the cavity of the scrotum.


a steroid hormone produced by the testes; it promotes the development of male sex characteristics and regulates male reproductive function; the primary and most potent androgen secreted by the testes.

Thrombin (THROM-bin)

The enzyme derived from prothrombin that converts fibrinogen to fibrin.

Thrombin Time

The time required for fibrinogen to form thrombin; measured by adding exogenous thrombin to citrated plasma and determining the time to clot formation.

Thrombocytopenia (throm-bo-si-to-PEE-nee-uh)

A decrease in blood platelets.

Thromboembolism (throm-bo-EM-bo-lizm)

An embolism caused by a mass of aggregated blood factors (thrombus); obstruction of a blood vessel with thrombotic material carried by the blood stream from the site of origin.


Causing thrombosis or coagulation of the blood.

Thrombolysis (throm-BOL-ih-sis)

The phenomenon by which thrombi (plural of thrombus) are lysed (dissolved) by a series of events, the most important of which involves the local action of plasmin within the substance of the thrombus. Intracoronary thrombolysis: the lysis of clots by thrombolytic agents introduced into the coronary arteries; used in therapy of myocardial infarction.

Thromboprophylaxis (throm-bo-pro-fie-LAK-sis)

Prevention of thrombosis.

Thrombus (THROM-bus)

An aggregation of blood factors, primarily platelets and fibrin with entrapped blood cells; frequently causing vascular obstruction at the point of its formation. Some authorities differentiate thrombus formation from simple coagulation or clot formation.

Toxic, toxin

A poisonous substance that can damage living cells and tissue inside the body. Toxins can enter the body from the outside environment (drugs, alcohol, pollution) or they can be produced inside the body as waste by-products of metabolism.

Tracheoesophageal Fistula (TEF) (TRAY-kee-oh-uh-SAW-fuh-JEE-ul FIST-yoo-luh)

A condition that occurs when there is a gap between the upper and lower segments of the esophagus. Food and saliva cannot pass through.

Transgenic (trans-GEN-ik)

Pertaining to the insertion by bio-technical means of a foreign gene or genes into the genetic makeup of an organism.

Transverse Colon (TRANZ-vurs KOH-lun)

The part of the colon that goes across the abdomen from right to left.

Travelers' Diarrhea (TRAV-lurz dy-uh-REE-uh)

An infection caused by unclean food or drink. Often occurs during travel outside one's own country. See also gastroenteritis.


A type of blood fat. The body needs insulin to remove this type of fat from the blood. When diabetes is under control and a person's weight is what it should be, the level of triglycerides in the blood is usually about what it should be.

Triple-Therapy (TRIH-pul THEH-ruh-pee)

A combination of three medicines used to treat Helicobacter pylori infection and ulcers. Drugs that stop the body from making acid are often added to relieve symptoms.

Tropical Sprue (TRAH-pih-kul sproo)

A condition of unknown cause. Abnormalities in the lining of the small intestine prevent the body from absorbing food normally.

Tumescence (too-MESS-ens)

a swelling.

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