At adrenal glands or adrenals, located one over each kidney, are made up of two quite distinct secretory tissues.
One of them forms the outer part of the gland, the cortex, while the other forms its innermost portion, the marrow.
The adrenal medulla produces two main hormones: adrenaline (or epinephrine) and norepinephrine (or norepinephrine). These two hormones are chemically similar, produced from biochemical modifications to the amino acid tyrosine.
When a person experiences a stressful situation (fright, high emotion situations etc.), the nervous system stimulates the adrenal medulla to release adrenaline into the blood. Under the action of this hormone, the blood vessels in the skin contract and the person becomes pale; Blood is concentrated in the muscles and internal organs, preparing the body for a vigorous response.
THE adrenaline It also produces tachycardia (increased heart rate), increased blood pressure and increased excitability of the nervous system. These metabolic changes allow the body a quick response to the emergency.
THE norepinephrine It is released at more or less constant doses by the adrenal medulla, regardless of adrenaline release. Its main function is to maintain blood pressure at normal levels.
The hormones produced by the adrenal cortex are steroids, that is, cholesterol derivatives and known generically as corticosteroids. The main ones are the glucocorticoids and the mineralocorticoids.
Glucocorticoids act in the production of glucose from proteins and fats. This process increases the amount of glucose available to be used as fuel in response to a stressful situation. The main glucocorticoid is the cortisol, also known as hydrocortisone. In addition to its effects on glucose metabolism, hydrocortisone decreases the permeability of blood capillaries. Because of these properties, hydrocortisone is used clinically to reduce inflammation caused by allergic processes, among other things. Prolonged use of hydrocortisone should be avoided because hydrocortisone has the property of depressing the body's defense system, making the body more susceptible to infections.
Mineralocorticoids regulate the balance of water and salts in the body. Aldosterone, for example, is a hormone that stimulates salt resorption by the kidneys. This causes water retention with consequent increase in blood pressure. Aldosterone release is controlled by substances produced by the liver and kidneys in response to variations in salt concentration in the blood.
Emotional state, adrenal hormones and diseases
Emotional depression can act on the hypothalamus, causing it to stimulate the adrenal glands. As a result, blood depression rises and the body's overall metabolism is altered to allow the body to cope with stress. Persistence of such a situation can result in illness. High blood pressure, for example, predisposes the body to various types of heart disease.
It is now known that the persistence of high blood cortisol levels, as occurs in chronic stress, depresses the immune system, which makes the body more susceptible to infections and contributes to ulcers, hypertension, arteriosclerosis and possibly diabetes. Melito