Your endocrine system controls your hormones. They affect nearly every bodily function. When any part of this system isn’t working properly, your health suffers. We're here to help.
Adrenal glands, which are also called suprarenal glands, are small, triangular glands located on top of both kidneys. An adrenal gland is made of two parts--the outer region is called the adrenal cortex and the inner region is called the adrenal medulla.
Adrenal glands work interactively with the hypothalamus and pituitary gland in the brain.
Learn more about adrenal glands.
The parathyroid glands are two pairs of small, oval-shaped glands located adjacent to the two thyroid gland lobes in the neck.
Parathyroid glands produce parathyroid hormone, which plays a key role in the regulation of calcium levels in the blood. Precise calcium levels are important in the human body, since small deviations can cause muscle and nerve impairment.
The thyroid gland is located in the front of the neck (just above the breastbone and below the Adam's apple). The small, two-inch gland consists of two lobes, one on each side of the windpipe, connected by a small bridge of thyroid tissue called the isthmus.
The thyroid tissue is made up of two types of cells: follicular cells and parafollicular cells. Most of the thyroid tissue consists of the follicular cells, which secrete the iodine-containing thyroid hormones. They consist of thyroxine (T4) and triiodothyronine (T3). The parafollicular cells (also called C cells) secrete the hormone calcitonin. Calcitonin is a weak hormone that helps in the regulation of calcium in some animals. In humans, calcitonin has only a minor role in calcium regulation. When the thyroid is completely removed because of cancer or disease, the removal of these C cells produces no problems with calcium regulation. The follicular cells require an adequate supply of iodine in order to produce the thyroid hormones.
Learn more about the thyroid gland.