The thyroid gland is a gland that plays a major role in the metabolism, growth and development of the human body. It helps regulate many of its functions by releasing hormones into the bloodstream.
Structure of the thyroid gland
The thyroid gland weighs an average of 20 to 60 grams. It is located at the front of the neck, under the larynx. It has a butterfly-like shape – two lateral lobes adhere to the trachea and are connected in front by a narrow band of tissue. The thyroid gland is surrounded by two fibrous formations. The outer layer connects to the muscles of the larynx and many important vessels and nerves. Between it and the inner layer is loose connective tissue, allowing the thyroid gland to move and change its position during swallowing. The parenchyma of the thyroid gland is made up of many small follicles that store hormones.
Hormone production
The thyroid gland produces three hormones. In the follicular cells – triiodothyronine, also known as T3, and tetraiodothyronine, also known as thyroxine or T4. In turn, the so-called C cells produce calcitonin, which is involved in calcium and bone metabolism.
T3 and T4 increase the basal metabolism. They make all the body’s cells work harder, so they also need more energy. This causes an increase in body temperature, a faster pulse and stronger heartbeat, promotes brain development and growth in children, and activates the nervous system, leading to improved concentration and reflexes. Since the hormones released by the thyroid gland regulate metabolism, its work has an impact on body weight. Healthy meals can positively affect thyroid function, and weight gain with a well-balanced diet is far less likely.
The body’s need for hormones is variable. The thyroid gland produces more of them in situations that require extra energy – for example, during periods of growth, during pregnancy or when it is cold. To produce the right amount of hormones, the organ needs the help of another gland – the pituitary gland.
Some of the main building blocks of hormones are amino acids and iodine. The human body is unable to synthesize this element on its own, so it must be supplied with food. The richest in iodine are marine fish (for example, cod, pollock or halibut), seafood and algae. The element is also commonly added to food salt.