The human body has two adrenal glands. They are located atop the kidneys. The right adrenal gland has a triangular shape while the left one is in the form of a semi-crescent.
~ Adrenal gland structure ~
Adrenal glands consist of two parts – a cortex and a medulla.
The cortex is divided itself into three zones. The Zona Glomerulosa is the outermost layer, which produces mineralocorticoids responsible for blood pressure regulation.
Zona Fasciculata is the middle layer. It produces glucocorticoids, mainly cortisol. Cortisol increases the resistance of the human body towards harmful agents. It also decreases the strength of inflammatory reactions.
Zona Reticularis is the inner layer that produces sexual hormones. These hormones are androgen in men and estrogen and progesterone in women.
The adrenal glands receive blood from several arteries. In the interior of the glands, the arteries branch and turn into wide capillaries. The blood from these capillaries comes in close contact with the gland’s cells that produce hormones.
Blood flows out of the adrenal gland through a system of veins. The gland is poor in lymph vessels.
~ Adrenal gland function ~
Nearly 30 types of active substances have been isolated from the adrenal gland.
The most important hormones that the gland produces include aldosterone, cortisol and the sexual hormones.
Aldosterone regulates the electrolyte metabolism in the human body. It stimulates the reabsorption of sodium in the kidneys, the sweat glands and the stomach lining.
Further, aldosterone increases the secretion of potassium in urine, sweat and saliva. This mechanism is needed to keep the optimal amount of water in the human body, thus maintaining arterial pressure and the alkaline-acidic balance.
Cortisol is tightly connected to the regulation of carbohydrate, lipid and protein metabolism. It decreases the protein storage in cells and increases the amount of amino acids in the plasma.
The sexual hormones are connected to the masculinity or femininity of an individual and the formation of genital differences. Men and women secrete both types of gender hormones but the one that is not connected to the sexual identity of the individual is produced in minor amounts.
~ Adrenal gland problems ~
The hypofunction of the adrenal gland (lowered production) results in Addison’s disease. The individual experiences a weight lost, low blood pressure, fatigue, fainting and diarrhea.
Hyperfunction of the adrenal gland occurs in the case of cancerous formation. This condition results in the hyperproduction of either male or female sexual hormones. The hyperfunction in children causes early puberty. In the case of adults, it leads to irregular menstruation and other reproductive problems.
Sources of information:
MedLinePlus Medical Encyclopedia
National Institute of Health
University of Maryland Medical Center