Question

What role does the hypothalamus, pituitary, and thyroid axis play in maintaining body temperature and metabolic rate?

Answer 1

The hypothalamus intellects at low circulating levels of thyroid hormone (Triiodothyronine (T3) and Thyroxine (T4)) and responds by releasing thyrotropin-releasing hormone (TRH). The thyrotropin-releasing hormone stimulates the pituitary gland to release thyroid-stimulating hormone. The TSH stimulates the thyroid gland to release thyroid hormone until levels in the blood return to normal. Thyroid hormone uses negative feedback control over the hypothalamus and anterior pituitary. Therefore, hypothalamus controls the release of TRH and anterior pituitary gland controls TSH .

Thyroxine hormone helps in maintaining of rate of metabolism and body heat. T3 and T4 increase basal metabolic rate and the process of thermogenesis. They are transcription factors, which control the process of protein transcription. T3 increases basal metabolic rate more and more rapidly, but shorter half life. T4 is less active and takes longer, but longer half-life.

The hypothalamus is the processing center in the brain, which controls the temperature of body. It occurs by activating modifications to effectors, such as sweat glands and muscles controlling body hair. Heat stroke occurs when the body becomes too hot and hypothermia when the body becomes too cold. Temperature receptors, which are present in the skin. It detects changes in the external temperature. They pass this information to the processing center in the brain, known as hypothalamus. The hypothalamus has temperature receptors to detect changes in the temperature of the blood. It automatically activates changes to the effectors to ensure the temperature of body remains constant.