Chemical substances made by the thyroid gland, which is located in the front of the neck. This gland uses iodine to make thyroid hormones, which are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism), and are involved in the circadian rhythms that govern sleep, among other essential functions.
The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3). Thyroid stimulating hormone (TSH), which is produced by the pituitary gland, acts to stimulate hormone production by the thyroid gland. The pituitary gland is stimulated to make TSH by the hypothalamus gland in the brain.
The thyroid also makes the hormone calcitonin, which is involved in calcium metabolization and stimulating bone cells to add calcium to bone. See calcitonin, thyroxine, triiodothyronine.
- Thyroid hormone receptor
A molecule that receives a thyroid hormone and permits it to dock on the nuclear membrane of a cell. The thyroid hormone receptors (THRs) belong to a family of nuclear receptors that function as hormone-activated transcription factors and act by modulating the expression of genes. THRs bind DNA in the absence of hormone, usually suppressing […]
- Torsion fracture
A fracture, also called a spiral fracture, in which a bone has been twisted apart.
The most common of the focal dystonias, a state of excessive or inadequate muscle tone in the muscles in the neck that control the position of the head. Torticollis can cause the head to twist and turn to one side. The head may also be pulled forward or backward. Torticollis can occur at any age, […]
- Torticollis, congenital
A deformity of the neck that is present at birth. Congenital torticollis is due to shortening of the neck muscles. Congenital torticollis tilts the head to the side on which the neck muscles are shortened, so that the chin points to the other side. The shortened neck muscles are principally supplied by the spinal accessory […]
An act by which severe pain or suffering, whether physical or mental, is intentionally inflicted on a person, for a purpose such as obtaining information or a confession, punishment, intimidation or coercion, or for any reason based on discrimination of any kind. Survivors of torture often suffer from physical and psychological symptoms and disabilities. There […]