ADRENAL GLAND

ADRENAL GLAND

Function

The adrenal gland secretes various hormones that affect different parts of the body. Some are necessary for survival, notes Frederic Martini, Ph.D., in “Fundamentals of Anatomy & Physiology.” The anterior pituitary of the brain regulates part of the gland, telling it when certain hormones need to be made. Parts of the nervous system and the kidneys stimulate the production of other adrenal hormones.

Structure

The outer part of the adrenal gland, the adrenal cortex, constitutes 90 percent of the gland. The cortex has three zones. The zona glomerulosa is the outermost zone and makes the hormone aldosterone from cholesterol. The next is the zona fasciculata, which makes hormone cortisol, also from cholesterol. The zona reticularis is the third area and is where androgens, or male hormones, are made from cholesterol. The inner part of the adrenal gland is called the adrenal medulla. It makes substances called epinephrine and norepinephrine.