There are two adrenal glands and each triangular-shaped gland sits on top of kidney.  The term adrenal comes from the roots "ad" for "stuck to" and "renal" meaning kidney.  The adrenal glands are made of two major parts: the cortex, or outer part, and the medulla, the middle part.  The adrenal cortex produces and secretes the glucocorticoids, mineralocorticoids, and "sex hormones."  The sex hormones include androgens, estrogens, and progestins.  The adrenal medulla produces the so-called catecholamines that help regulate the fight-or-flight response, including: dopamine, epinephrine, and norepinephrine.  All of these hormones will be described in more detail below.

What are the adrenal glands?

The adrenal glands are two small pyramid-shaped glands that sit on top of the kidneys.  The adrenals can be separated into two major parts based on the hormones they secrete.  The adrenal cortex, or outer layer of the gland, produces and secretes the glucocorticoids, mineralocorticoids, and "sex hormones."  The sex hormones include androgens, estrogens, and progestins.  The adrenal medulla produces the so-called catecholamines that help regulate the fight-or-flight response, including: dopamine, epinephrine, and norepinephrine.

What hormones are secreted by the adrenal cortex and what do they do?

Glucocorticoids are hormones that have multiple effects on the production of sugars and proteins in the body.

Mineralocorticoids are hormones that regulate the sodium and fluid balance of the body.  These hormones interact with chemicals produced by the kidneys to affect the amount of water and sodium that is excreted in the urine.

"Sex hormones"  (including androgens, estrogens, and progestins) are hormones that help the body prepare for puberty and reproduction.  They generally have minor effects when compared to the sex hormones produced by the ovaries or testes.

What hormones are secreted by the adrenal medulla and what do they do?

Dopamine is a hormone that has different effects on the heart and blood vessels.  It works similar to epinephrine to prepare the body for the "fight or flight" response.

Epinephrine is a hormone that is sometimes called "adrenaline."  As you may know, a kick of adrenaline helps the body prepare for emergency or stressful situations.  Epinephrine speeds up the heart and breathing rate.  This prepares the body for "fight or flight."  Which means, if you run into an angry bear in the woods your body will be ready to run!

Norepinephrine is a hormone similar to epinephrine that prepares the body for the "fight or flight" response.  Norepinephrine works mostly on blood vessels, causing them to constrict.  This increases the blood pressure and helps divert blood to the most vital organs (i.e., the heart and brain).

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