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The Endocrine System

The endocrine system consists of glands or parts of glands whose secretions (called hormones) are distributed in the human body by means of the bloodstream.

The major organs of the endocrine system are the hypothalamus, the pituitary gland, the thyroid gland, the parathyroid glands, the islets of the pancreas, the adrenal glands, the testes, and the ovaries. During pregnancy, the placenta also acts as an endocrine gland in addition to its other functions.

To find out more about the endocrine system point your mouse to the glands in the image.

The endocrine system is composed of glands that produce hormones that released into the circulation for transport to target tissue sites of action remote to the site of production. Endocrine glands include the pineal, parts of the brain, pituitary, thyroid, pancreas, adrenal, and the gonads (ovaries and testis). In pregnant women the placenta also functions as an endocrine gland becoming the principle site of steroid production during pregnancy. The hormones produced by these glands may be either proteins or steroids such as the sex steroids: estrogen, progesterone and testosterone.

Humans have two systems of internal communication: the nervous system and the endocrine system. The endocrine system controls the delivery of messages through the release of chemicals known as hormones. Hormones are secreted directly into the blood by endocrine glands. Endocrine glands are found throughout the body and are responsible for releasing more than 50 hormones. Hormones control a number of essential functions in the body, including growth and development. For example, thyroxine, produced in the thyroid gland influences metabolic rate. Insulin and glucagon are produced in the pancreas and regulate glucose levels in the blood.