Dictionary

TMJ Temporomandibular joint.

TMJ syndrome Temporomandibular joint syndrome.

tobacco A South American herb (Nicotiana tabacum) whose leaves contain 2 to 8 percent nicotine and serve as the source of both smoking and smokeless tobacco and the basis of great health hazards.

toc-, toco- Prefix meaning childbirth, as in tocolysis (the slowing or halting of labor). Sometimes spelled tok- and toko-.

tocolysis The slowing or halting of labor during the birth process.

thyroid binding globulin A blood protein that binds with the thyroid hormone thyroxine (T4).

thyroid gland See gland, thyroid.

thyroid hormone A chemical substance that is made by the thyroid gland and is essential for the function of every cell in the body. The thyroid gland uses iodine to make thyroid hormones, which help regulate growth and the rate of chemical reactions (metabolism) and are involved in the circadian rhythms that govern sleep, among…

thyroid hormone organification defect IIb See Pendred syndrome.

thyroid scan An image taken of a patient’s thyroid gland after the patient swallows radioactive iodine or technetium. The image shows the thyroid gland in action as it accumulates radioactive material. Thyroid scanning is used to determine how active thyroid tissue is in manufacturing thyroid hormone. This can help a physician determine whether inflammation of…

thyroid-stimulating hormone A hormone that is produced by the pituitary gland at the base of the brain in response to signals from the hypothalamus gland in the brain. Abbreviated TSH. TSH promotes the growth of the thyroid gland in the neck and stimulates it to produce more thyroid hormones. When the amount of thyroid hormones…

thyroid-stimulating immunoglobulin A form of immunoglobulin G (IgG) that can bind to thyroid stimulating hormone (TSH) receptors on the thyroid gland. Abbreviated TSI. TSIs mimic the action of TSH, causing excess secretion of thyroxine and triiodothyronine. The TSI level is abnormally high in persons with hyperthyroidism due to Graves disease.