Everyone has two adrenal glands, also called suprarenal glands, one located on top of each of the kidneys. Adrenal glands produce essential hormones which are necessary for controlling the body's metabolism, immune system, response to stress and sexual development. Each adrenal gland consists of two parts which have completely different functions within the body.
Anatomy
The adrenal glands are triangular in shape and orange in color, and are about 1/2-inch high and 3-inches long, according to Endocrine Web. Each gland consists of two parts, which release different hormones and perform different jobs. The center of the gland, or the medulla, is surrounded by an outer cortex.
Function
The adrenal glands work in concert with the hypothalamus and the pituitary gland. The hypothalamus stimulates the pituitary with corticopropin-releasing hormones. These hormones cause the pituitary to produce corticopropin hormones, which in turn stimulate the adrenal glands to produce corticosteroid hormones.
Adrenal Cortex
The outer portion of the adrenal gland, the adrenal cortex, releases hormones directly into the bloodstream. These hormones affect body metabolism, blood chemicals and some types of body characteristics. The corticosteroid hormones, hydrocortisone and corticosterone, control the body's use of fats, proteins and carbohydrates, and also play a role in the body's immune system response. Also produced by the adrenal cortex are aldoserone, which maintains blood volume and blood pressure, and androgenic steroids, partially responsible for the development of male characteristics.
Adrenal Medulla
The inner part of the adrenal gland, the adrenal medulla, produces substances called catecholamines which regulate the body's response to physical or emotional stress. Epinephrine--also called adrenaline--acts to elevate heart rate and heart contractions, and increases the flow of blood to the brain and muscles. Norepinephrine, or noradrenaline, serves to increase blood pressure, according to the University of Maryland Medical Center.
Disorders
Normal functioning of the adrenal glands can be disrupted by disorders that cause them to produce too much or not enough of the adrenal hormones. In Cushing's syndrome, the body is exposed to an excessive amount of the hormone cortisol. It can be caused by tumors, medications that force the body to overproduce cortisol, or a genetic form of Cushing's syndrome. Congenital adrenal hyperplasia is a genetic disorder in which the body does not produce enough cortisol. Tumors of the pituitary gland can also lead to adrenal imbalances. If a tumor causes the adrenal gland to reduce its release of hormones during times of physiological stress, it can result in a dangerous condition called Addison's disease, according to the National Institutes of Health.
