Britannica Sources used in this answer

Which glands and tissues make up the human endocrine system?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram showing the locations of major human endocrine glands in male and female bodies, including pineal gland, hypothalamus, pituitary gland, parathyroid glands, thyroid gland, thymus, adrenal glands, pancreas, kidneys, testes, and ovaries. — Endocrine system The glands of the human endocrine system.

The human endocrine system is composed of various secretory organs, discrete glands, and specialized tissues that synthesize and secrete hormones to regulate physiological processes.1

Primary Endocrine Glands and Tissues

Many endocrine glands are recognizable organs with defined borders, including:
* Pituitary gland: Often called the master gland, it consists of anterior, posterior, and intermediate lobes that regulate growth, metabolism, and reproduction.1
* Thyroid gland: Regulates cellular metabolism and calcium levels.1
* Adrenal glands: Located above the kidneys, these glands produce hormones like cortisol, aldosterone, and catecholamines (epinephrine and norepinephrine) to manage stress and fluid balance.1
* Gonads: The testes and ovaries produce sex hormones essential for development and reproduction.1
* Parathyroid glands: Manage serum calcium concentrations.1
* Pineal gland: Regulates circadian rhythms via melatonin.1

Embedded and Diffuse Endocrine Tissues

Other endocrine components are embedded within larger structures or function as part of other systems:
* Pancreas: Contains the islets of Langerhans, which secrete insulin and glucagon.1
* Hypothalamus: A critical neurosecretory center that controls the pituitary gland.12
* Gastrointestinal Tract: Tissues in the stomach and duodenum secrete hormones like gastrin and secretin.1
* Other Organs: The liver, kidneys, heart, lungs, and skin also possess endocrine functions.1