The Thyroid Gland

The thyroid gland is located at the front of the neck just below the Adam’s apple. It has two lobes and the gland is butterfly shaped. The thyroid is one of the largest endocrine glands, weighing up to 60 grams in adult humans.

The thyroid gland controls the metabolic rate of all the tissues of the body. Metabolic rate means the rate at which the cells produce and consume energy, so the thyroid gland is in charge of energy regulation in every cell of our body. This encompasses almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate.

Thyroid hormone production is controlled by the pituitary gland, which in turn is controlled by the hypothalamus.

The pituitary gland produces thyroid-stimulating hormone (also known as TSH and as thyrotropin). TSH then stimulates the thyroid gland in order for it to secrete thyroxine (abbreviated to T4) and a very small amount of triiodothyronine (also known as T3). 

The thyroid gland also secretes the iodotyrosines (T1 and T2) but far less is known about what they actually do and if they have any real significance to our health.

In addition to the thyroid hormones (T3 and T4) and the iodotyrosines (T1 and T2) the thyroid gland also produces calcitonin.