The adrenal glands, as the term suggests, are a pair organ located in close proximity to the kidneys, they are triangular and their size is 5 x 1.5 x 0.5 cm. Anatomically speaking they lie near the spine, at the level of the 11th rib. They consist of two functionally distinct parts, the cortex and medulla. Both cortex and medulla produce important hormones. The adrenal glands are essential organs involved in a complex system of hormonal regulation of our body. You can imagine the mediators, i.e. hormones, as letters, which distant organs use to communicate with each other. These "letters" are sent to the organs by blood. This ingenious system of our body guarantees that everything works as it should, that the "letter" - a hormone gets to the correct address and informs the correct addressee. Each organ has its exact location and a different "mailbox", where only the letters of the "right" size and shape fit. This ensures that the letter is received "in to good hands" - to the correct organ.
Adrenal glands are controlled by the brain
Also adrenal glands are controlled by higher centers. The main control section is located in the brain. If you are expecting a grand "postal headquarters", you are wrong. It is a small pea-sized body about 1 - 1.5 cm large attached to the base of the brain, and is called the pituitary gland. This small organ is superior to the much larger sized thyroid gland, ovaries in women, testes in men and also adrenal glands. This list of functions does not end; it is also involved in the management of growth and is involved in metabolism and immunity.
How does the adrenal gland control work?
The main headquarters (the pituitary gland) are in the brain, while the executive body, the adrenal glands, is stored in the abdominal cavity. From the main headquarters a request is sent through the bloodstream, which reaches the adrenal glands, which begin to accomplish the command: "Produce hormones!" As each employee can be late with work, or on the other hand is a workaholic they may release much more hormones than needed in the current moment. Adrenal hormones are released into the blood. This ensures that the pituitary gland is retroactively informed about the fulfilled tasks. If not satisfied with the work of the adrenal glands, the pituitary gland releases more letters with the message "Work less, it is enough for the body. Relax!! "or reminders "Your activity is low, increase the pace of work!!".
Adrenal hormones – medulla vs. cortex
The adrenal cortex is controlled exclusively by the pituitary gland, but also kidneys are involved in the control of the cortex. The adrenal medulla on the contrary is independent on the pituitary gland. It produces a well-known stress hormone adrenaline, the effects of which you all know very well. We encounter stressful situations on a daily basis. We all know well behavioral changes of our body before an exam, graduation exam, public performance, a first date or when wandering through the dark woods. The adrenal hormone adrenaline prepares the body for "flight" or "fight". At least it was so in the days of the mammoth hunters or the Napoleon wars. Today we are not endangered by a wild animal or a soldier from foreign troops so often, but stressful situations continue to accompany all living beings, including humans. In other words, today we are experiencing the same feelings, accompanied by the same reactions of our body as a mammoth hunter before tens of thousands of years or soldiers in the early 19th century. Reactions such as palpitations, rapid pulse, rapid and deep breathing and sometimes shortness of breath, dry mouth, trembling limbs, and many others.
Adrenal cortex produces other hormones known as steroid hormones, also called steroids. Among the steroids belong well-known glucocorticoids (cortex = skin, gluco prefix), which affect the metabolism of sugars, less fat and protein. Furthermore, the mineralocorticoid aldosterone (prefix mineral - affects the management of minerals, in particular sodium and potassium), has an effect on blood pressure, renal blood flow and the management of body water (holds water) and the above mentioned minerals. Another group of hormones of the adrenal cortex are sex hormones, both male and female. For women are male sex hormones, particularly testosterone, necessary for proper sexual development and growth of pubic hair.
For your information: In castrated males adrenal testosterone is insufficient to maintain the male sexual characteristics. Formation of the female sex hormone, estrogen, which is produced by the adrenal cortex, is also insufficient to compensate for loss after the removal of the ovaries. Interestingly, however, it is sufficient to stimulate the growth of breast tumors after ovary removal. This is in certain breast cancers whose growth is dependent on hormonal stimulation.
Adrenal glands and cortisol
The best known hormone of the adrenal cortex is a glucocorticoid cortisol. What are its functions? It is essential for carbohydrate metabolism and its deficiency leads to hypoglycemia. This means that the sugar levels in the body are low. Conversely excess induces hyperglycemia, a high blood sugar and diabetes-like symptoms. Another function of the adrenal hormone is that it increases protein breakdown. The basic building blocks of proteins, called amino acids, are used by the liver to produce sugar. Excess of cortisol leads to loss of muscle mass and fat redistribution, thinning of the skin, which is then thin, highly vulnerable to breakage and is similar to a sheet of parchment, also causes osteoporosis, or bone loss, which then are prone to fracture (see Cushing's disease).
High levels of this hormone and other corticoids suppresses the immune system, they act immunosuppressive. This effect is widely used in medicine for a number of diseases that are caused by high activity of the immune cells like skin diseases, inflammations, asthma, autoimmune processes (a condition where the immune cells attack and kill the body's own cells), blood diseases, with conditions after transplantation etc.High levels of cortisol increase blood pressure, blood fats and cholesterol, increasing the risk of heart diseases and blood vessel diseases. Elevated levels of the adrenal hormone cortisol can cause gastric and duodenal ulcers or complicate the disease.