Thyroid hormones are chemical substances produced by the thyroid gland, which is situated at the front of the neck. This gland utilizes iodine to produce hormones that are crucial for the functioning of every cell in the body. These hormones play a significant role in controlling growth and metabolic rate, as well as being involved in circadian rhythms that regulate sleep and other vital functions. The two primary thyroid hormones are thyroxine (T4) and triiodothyronine (T3). The production of these hormones is stimulated by the thyroid-stimulating hormone (TSH), which is secreted by the pituitary gland. The pituitary gland, in turn, is prompted to produce TSH by signals from the hypothalamus in the brain. Additionally, the thyroid gland produces calcitonin, a hormone that is important for calcium metabolism and encourages bone cells to incorporate calcium into bones. For further information, refer to calcitonin, thyroxine, and triiodothyronine.
