The adrenal glands are located in the trunk of the human body, where they rest like caps over the top of the kidneys. These organs are responsible for the production of hormones that influence the levels of sodium, glucose and antibodies in the blood. They also help regulate blood pressure, fight inflammation and are involved in the body's physiological responses to stress. Adrenal gland disease can be classified into two main types of disorder: overactivity of the gland and underactivity of the gland, each of which results in different effects, depending upon which area of the gland is involved.
Adrenal Cortical Hyperfunction
Gary Thibodeau, Ph.D., author of "The Human Body in Health and Disease," explains that the adrenal gland is actually composed of two separate endocrine glands--the cortex and the medulla. The adrenal cortex is the outer layer of the gland. Three separate layers of cells exist in the cortex, each producing different hormones. Cortisol, aldosterone and sex hormones are all secreted by the adrenal cortex.
Adrenal cortical hyperfunction occurs when the adrenal cortex produces more hormone than is normally necessary. Cushing's disease results from an excess of glucocorticoid hormones produced by the adrenal gland. This disorder results in a redistribution of body fat that causes a moon-faced appearance, along with a buffalo hump on the upper back.
Adrenal Cortical Hypofunction
When the adrenal cortex is functioning at lower than normal levels of productivity, less hormone is produced. Loyola University's Stritch School of Medicine refers to this as adrenal cortical hypofunction.
Addison's disease, a condition characterized by muscle weakness, lower blood glucose levels and weight loss, results when there is an abnormally low level of adrenal cortex hormones.
Adrenal Medulla Hyperfunction
The adrenal medulla is the inner layer of the adrenal gland. It produces two hormones that are involved in the body's response to stress--epinephrine and norepinephrine. A decrease in these hormones does not impact human health, but an increase, especially an increase of prolonged duration, can result in serious complications.
Hyperfunction of the adrenal medulla is most often the result of a tumor located in the medulla. Pheochromocytoma is the most common tumor found in the adrenal medulla of adults, according to the Virginia Commonwealth University Department of Pathology. It causes overactivity of the medulla, which produces excess amounts of hormone, resulting in hypertension.
References
- Loyola University Health System: Stritch School of Medicine: Adrenal Gland
- "The Human Body in Health and Disease"; Gary Thibodeau, PhD and Kevin Patton PhD; 2002
- VCU Department of Pathology: Endocrine Disorders and Diabetes: Endocrine Disorders Continued
