Where are the adrenal glands located? What is their function?
There are two adrenal glands and they rest on top of each kidney. Adrenal glands secrete hormones : adrenaline, noradrenaline, mineralocorticoid, glucocorticoid & androgens.
Here is a diagram showing the location of adrenal glands on top of each kidney :
Adrenal gland has two parts, anatomically : adrenal cortex and adrenal medulla. These two act like two separate endocrine glands. The adrenal medulla produces large amounts of the hormone adrenaline, also known as epinephrine, and small amounts of norepinephrine or noradrenaline. Epinephrine and norepinephrine are commonly referred to as the fight-or-flight hormones because they get the body prepared for stressful situations that require vigorous physical activity.
This diagram shows the effects of epinephrine (adrenaline) on different organs of body :
The adrenal cortex makes up the bulk of the adrenal gland. Its cells are organized into three layers of cells, forming an inner, a middle, and an outer region of the cortex.
The outer layer of the adrenal cortex secretes a group of hormones called "mineralocorticoid hormones" because they regulate the concentration of mineral electrolytes. The most important of these hormones is aldosterone, which regulates sodium reabsorption and potassium excretion by the kidneys.
The middle layer of the adrenal cortex secretes cortisol, which is a "glucocorticoid hormone". Cortisol stimulates the liver to synthesize glucose from circulating amino acids. It causes adipose tissue to break down fat into fatty acids and causes the breakdown of protein into amino acids. The action of cortisol helps the body during stressful situations and helps maintain the proper glucose concentration in the blood between meals. Cortisol also helps reduce the inflammatory response.
Cells in the inner layer of the adrenal cortex produce small amount of the androgens in both male and female.