Endocrine system
Physiology · Human Anatomy · Medicine
Say it: EN-duh-krin SIS-tum
The endocrine system is the set of glands and cells that release hormones into the blood to regulate growth, metabolism, reproduction and more.
Also: hormonal system
Definition
What is the endocrine system?
The endocrine system is the body's chemical signaling network. It is made up of endocrine glands, which have no ducts and release hormones straight into the blood, along with hormone-making cells in many other organs. The main glands are the hypothalamus and pituitary in the brain, the pineal gland, the thyroid and parathyroid glands in the neck, the thymus, the adrenal glands, the islets of the pancreas, and the ovaries or testes. The heart, kidneys, stomach, intestines, fat tissue and even bone also release hormones.
Like the nervous system, the endocrine system coordinates the body and helps maintain homeostasis, but it works differently. Nerve signals act within milliseconds on specific cells, while hormones travel in the blood, take seconds to hours to act, and can have effects that last much longer. The two systems are closely linked, above all through the hypothalamus, which controls the pituitary gland. Endocrine glands differ from exocrine glands, such as sweat glands and digestive glands, which release their products through ducts; the pancreas is both.
Endocrine disorders, including diabetes mellitus, thyroid disease, Cushing syndrome and Addison disease, usually involve too much or too little of a particular hormone.
Word parts
Where does the term “endocrine system” come from?
- endo-
- withinGreek endon
- -crine
- to separate, secreteGreek krinein
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- HormoneA hormone is a chemical messenger released into the blood by a gland or cell that changes the activity of distant target cells with matching receptors.
- PancreasThe pancreas is a gland behind the stomach that sends digestive enzymes to the small intestine and releases insulin and glucagon into the blood.
- CortisolCortisol is a steroid hormone made by the adrenal cortex that helps the body cope with stress, raises blood glucose and dampens inflammation.
- InsulinInsulin is a peptide hormone made by beta cells in the pancreas that lowers blood glucose by helping body cells take up and store sugar.
- HomeostasisHomeostasis is the body's ability to keep internal conditions, such as temperature, blood glucose and pH, steady while conditions around it change.
- Diabetes mellitusDiabetes mellitus is a chronic disease in which blood glucose stays too high because the body makes too little insulin or cannot use it well.
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Written for biofideX in plain words, after checking these references:
- OpenStax Anatomy and Physiology 2e, 17.1 An Overview of the Endocrine System
- NCI SEER Training: Introduction to the Endocrine System
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