Skip to main content

Endocrine System

On this page

The endocrine system includes the organs and glands that produce hormones.

Hormones are chemicals that are sent throughout the body and control functions such as growth and development, metabolism, sexual function, mood, temperature, and the sleep-wake cycle.

Endocrine organs and glands include the:

  • Pituitary gland
  • Hypothalamus
  • Thyroid and parathyroid glands
  • Adrenal glands

The pituitary is a small gland found inside the skull just below the brain and above the nasal passages, which are above the fleshy back part of the roof of the mouth (known as the soft palate). The pituitary sits in a tiny bony space called the sella turcica. The pituitary gland is connected directly to part of the brain called the hypothalamus.

The pituitary gland has 2 parts, the anterior pituitary and the posterior pituitary. Each has distinct functions.

The thyroid gland is in the front part of the neck, below the thyroid cartilage (Adam’s apple). In most people, the thyroid cannot be seen or felt. It is shaped like a butterfly, with 2 lobes — the right lobe and the left lobe — joined by a narrow piece of gland called the isthmus.

Behind, but attached to, the thyroid gland are 4 tiny glands called the parathyroids.

The adrenals are small glands that sit above each of the kidneys. The kidneys are located deep inside the upper part of the abdomen. Each adrenal gland has 2 parts: the outer part, the cortex, and the inner part, the medulla.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Last Revised: December 13, 2022

American Cancer Society Emails

Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.