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Hormones

A messenger molecule that helps coordinate the actions of various tissues; made in one part of the body and transported, via the bloodstream, to tissues and organs elsewhere in the body.

PubMed Health Glossary
(Source: NIH - National Institute of General Medical Sciences)

Insulin and protein interact in pancreatic beta cells. Click to enlarge

The yellow shows interactions between the hormone insulin (red) and protein (green) National Institutes of Health

Terms to know

Cells
The basic subunit of any living organism; the simplest unit capable of independent life. Although there are some single-celled organisms, such as bacteria, most organisms consist of many cells that are specialized for particular functions.
Endocrine Glands
A group of specialized cells that release hormones into the blood. For example, the islets in the pancreas, which secrete insulin, are endocrine glands.
Endocrine System
A system of glands and cells that make hormones that are released directly into the blood and travel to tissues and organs all over the body. The endocrine system controls growth, sexual development, sleep, hunger, and the way the body uses food.
Glands
A group of cells that secrete substances. Endocrine glands secrete hormones. Exocrine glands secrete salt, enzymes, and water.
Insulin
A hormone that helps the body use glucose for energy. The beta cells of the pancreas make insulin. When the body cannot make enough insulin, insulin is taken by injection or other means.
Pancreas
An organ that makes insulin and enzymes for digestion. The pancreas is located behind the lower part of the stomach and is about the size of a hand.
Proteins
A molecule made up of amino acids. Proteins are needed for the body to function properly. They are the basis of body structures, such as skin and hair, and of other substances such as enzymes, cytokines, and antibodies.

Terms to know

Cells
The basic subunit of any living organism; the simplest unit capable of independent life. Although there are s...
Endocrine Glands
A group of specialized cells that release hormones into the blood. For example, the islets in the pancreas, w...
Endocrine System
A system of glands and cells that make hormones that are released directly into the blood and travel to tissu...
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