Each adrenal gland has two layers — outer cortex and inner medulla. They are independent secretory organs and produce hormones different nature of the action. The cortical layer is constructed of steroidogenic tissue that produces steroid hormones. Inner medulla formed of chromaffin tissue, it produces hormones: catecholamine.
Corticosteroids — hormones of the cortical layer, they are involved in the regulation of metabolism, affects blood vessel tone and the immune system provide the body's resistance to various stresses and the constancy of its internal environment. The secretion of these hormones controlled by the pituitary gland.
The cells of the cortex produce hormones that regulate protein, carbohydrate, fat and mineral metabolism. These hormones affect the level of potassium and sodium in the blood, keeping her a certain concentration of glucose. With their participation increases the formation and deposition of glycogen in the muscles and liver, these functions perform the adrenal glands together with the hormones of the pancreas.
When hyperthyroidism adrenal cortex develops Addison's disease, it is called bronze. This disease is characterized by bronze skin tone, and fatigue, muscle weakness, and decreased immunity.
Adrenal medulla secretes adrenaline and noradrenaline. These hormones are produced in strong emotions — pain, anger, fear, for example, in case of emergency. The flow of these hormones in the blood helps to regulate vital body functions.
Hormones of the medulla of the adrenal gland cause rapid heartbeat, increased blood pressure and constriction of blood vessels, with the exception of the vessels of the brain and heart. When they enter in the blood increases breakdown of glycogen to glucose in liver cells and muscles, increases the excitability of the retina, improves the function of the vestibular and hearing AIDS. Under the influence of these hormones relax the muscles of lungs and there is inhibition of intestinal motility.
Biologically active substances of medulla help to adapt to adverse environmental influences, for example, by cooling or physical overload. Is changing the functions of the body under the action of extreme stimuli, his forces are mobilized for transfer of stress.