The adrenal glands are two glands that sit on top of the kidneys that are made up of two different areas.
- The outer part is the adrenal cortex which produces hormones that are vital to life, such as cortisol (which helps regulate metabolism and helps your respond to stress) and aldosterone (which maintains the right balance of salt and water while helping control blood pressure).
- The inner part is the adrenal medulla which produces less essential hormones, such as adrenaline (which helps your body react to stress).
Adrenal Cortex Hormones
The adrenal cortex produces two main groups of hormones; the glucocorticoids and mineralocorticoids. The release of glucocorticoids is triggered by the hypothalamus and pituitary gland. Mineralocorticoids are mediated by signals triggered by the kidney.
When the hypothalamus produces corticotrophin-releasing hormone (CRH), it stimulates the pituitary gland to release adrenal corticotrophin hormone (ACTH). These hormones, in turn, alert the adrenal glands to produce corticosteroid hormones.
There is a third class of hormone released by the adrenal cortex, known as sex steroids or sex hormones. The adrenal cortex releases small amounts of male and female sex hormones. However, their impact is usually surpassed by the greater amounts of other hormones (such as estrogen and testosterone) released by the ovaries or testes.
Adrenal Medulla Hormones
The hormones of the adrenal medulla are released after the sympathetic nervous system is stimulated, which occurs when you’re stressed. As such, the adrenal medulla helps you deal with physical and emotional stress.
You may be familiar with the fight-or- flight response; a process initiated by the sympathetic nervous system when your body encounters a threatening (stressful) situation.
The hormones of the adrenal medulla contribute to this response:
- Epinephrine: or called adrenaline. This hormone rapidly responds to stress by increasing your heart rate and rushing blood to the muscles and brain. It also spikes your blood sugar level by helping convert glycogen to glucose in the liver. (Glycogen is the liver’s storage form of glucose.)
- Norepinephrine: Also known as noradrenaline, this hormone works with epinephrine in responding to stress. However, it can cause narrowing of blood vessels. This results in high blood pressure.
Disorders can be related to overproduction or underproduction of one of these hormones with or without tumors of the adrenal gland.