Glossary of Terms & Definitions
Listed Alphabetically - "T"

Tachycardia: An abnormally rapid resting heart beat or pulse rate (over 100/min)

Tactile: Pertaining to the sense of touch.

Tannins: Any of a large group of plant-derived compounds. Tannins tend to be bitter tasting and may function in pigment formation and plant protection. 

Target cell: A cell whose activity is affected by a particular hormone.

Tetany: A condition of prolonged and painful spasms of the voluntary muscles, especially the fingers and toes (carpopedal spasm) as well as the facial musculature.

Tertile: One third of a sample or population.

Thalassemia major: Beta thalassemia is a genetic disorder that results in abnormalities of the globin (protein) portion of hemoglobin. An individual who is homozygous for the beta thalassemia gene (has two copies of the beta thalassemia gene) is said to have thalassemia major. Infants born with thalassemia major develop severe anemia a few months after birth, accompanied by pallor, fatigue, poor growth, and frequent infections. Blood transfusions are used to treat thalassemia major but cannot cure it. 

Thalassemia minor: Individuals who are heterozygous for the beta thalassemia gene (carry one copy of the beta thalassemia gene) are said to have thalassemia minor or thalassemia trait. These individuals are generally healthy but can pass the beta thalassemia gene to their children and are said to be carriers of the beta thalassemia gene.

Threshold: The point at which a physiological effect begins to be produced, for example, the degree of stimulation of a nerve which produces a response or the level of a chemical in the diet that results in a disease.

Thyroid: A butterfly-shaped gland in the neck that secretes thyroid hormones. Thyroid hormones regulate a number of physiologic processes, including growth, development, metabolism, and reproductive function.

Thyroid follicular cancer: A cancer of the thyroid gland that constitutes about 30% of all thyroid cancers. It has a greater rate of recurrence and metastases (spreading to other organs) than thyroid papillary cancer.

Thyroid papillary cancer: The most common form of thyroid cancer, which most often affects women of childbearing age. Thyroid papillary cancer has a lower rate of recurrence and metastases (spreading to other organs) than thyroid follicular cancer.

Total Parenteral Nutrition (TPN): Intravenous (I.V.) feeding that provides patients with essential nutrients when they are too ill to eat normally.

Transcription: (DNA or transcription); the process by which one strand of DNA is copied into a complementary sequence of RNA.

Transcription factor: Generally a protein that functions to initiate, enhance, or inhibit the transcription of a gene. Transcription factors can regulate the formation of a specific protein encoded by a gene. 

Transient ischemic attack (TIA): Sometimes called a small or mini stroke. TIAs are caused by a temporary disturbance of blood supply to an area of the brain, resulting in a sudden, brief (usually less than 1 hour) disruptions in certain brain functions.

Translation: (RNA translation) process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into a protein.

Trauma: An injury or wound.

Tremor: Trembling or shaking of all or a part of the body.

Triglycerides: A triglyceride consists of three molecules of fatty acid combined with a molecule of the alcohol glycerol. Triglycerides serve as the backbone of many types of lipids (fats). Triglycerides are the major form of fat in our diets and are also produced by the body.

Tuberculosis: An infection caused by bacteria called mycobacteria tuberculosis. Many people infected with tuberculosis have no symptoms because it is dormant. Once active, tuberculosis may cause damage to the lungs and other organs. Active tuberculosis is also contagious and is spread through inhalation. Treatment of tuberculosis involves taking antibiotics and vitamins for at least 6 months.

Typhoid: An infectious disease, spread by the contamination of food or water supplies with the bacteria called salmonella typhi. Food and water can be contaminated directly by sewage or indirectly by flies or poor hygiene. Though rare in the U.S., it is common in some parts of the world. Symptoms include fever, abdominal pain, diarrhea, and a rash. It is treated with antibiotics and intravenous fluids. Vaccination is recommended to those traveling to areas where typhoid is common.