Notes
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Hormones are your body's chemical messengers. They're any member of a class of signaling molecules that regulates physiology and behavior.
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They're substances that travel in your bloodstream to tissues or organs.
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A tiny amount of hormones is capable of causing significant changes in cells or even your whole body.
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Endocrine glands make hormones. The major endocrine glands are the pituitary, pineal, thymus, thyroid, adrenal, pancreas, and gonads.
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They work slowly, over time, and affect many different processes, including:
- growth and development;
 - metabolism;
 - sexual function;
 - reproduction;
 - mood swings;
 - activation of inhibition of the immune system;
 - wake-sleep cycle and other circadian rhythms.