Hyperthyroidism (cont.)
Thyroid hormone regulation--the
chain of command
The thyroid itself is regulated
by another
gland located in the brain, called the pituitary. In turn, the pituitary is regulated in part by thyroid hormone that is circulating in the blood (a
"feedback" effect of thyroid hormone on the pituitary gland) and in part by another
gland called the hypothalamus, also a
part of the brain.
The hypothalamus releases a hormone
called thyrotropin releasing hormone
(TRH), which sends a signal to the pituitary to release thyroid stimulating
hormone (TSH). In turn, TSH sends a signal to the thyroid to release thyroid
hormones. If overactivity of any of these three glands occurs, an excessive
amount of thyroid hormones can be produced, thereby resulting in
hyperthyroidism.
Hypothalamus - TRH
Pituitary- TSH
Thyroid- T4 and T3
The rate of thyroid hormone production is controlled by
the pituitary gland. If there is an insufficient amount of thyroid hormone
circulating in the body to allow for normal functioning, the release of TSH is
increased by the pituitary in an attempt to stimulate the thyroid to produce more thyroid
hormone. In contrast, when there is an excessive amount of circulating thyroid
hormone, the release of TSH is reduced as the pituitary attempts
to decrease the production of thyroid hormone.
Next: What causes hyperthyroidism? »
- Beta Blockers - Learn more about Beta Blockers, a drug that treats angina and other heart rhythm disorders, migraines, high blood pressure, panic attacks, and tremors. Generic and brand names are included in the article.
- Thyroid Blood Tests - Read about thyroid blood tests, which are used to diagnose disease of the thyroid such as hyperthyroidism and hyperthyroidism, as well as point to other diseases of the thyroid gland.
- Hypothyroidism - Learn about Hypothyroidism (underactive thyroid) including causes, symptoms (such as weight gain, fatigue, and depression), diagnosis, and treatment.
Latest Medical News
Specialty RSS
