Write a short note on the Adrenal gland.
The Adrenal Glands are found on top of each kidney. These are known as suprarenal glands. It has two divisions-Adrenal cortex and the Adrenal medulla.
1.Adrenal Cortex
The adrenal cortex is the outermost layer of the adrenal gland which is devoted to the production of aldosterone, cortisol, and androgens hormones. There are three layers of cortex called zones which can be examined and easily differentiated under a microscope:
Zona glomerulosa – It secretes mineralocorticoids like aldosterone
Zona fasciculata – It is responsible for producing corticosteroids like cortisol. Also secrets small quantities of androgens (such as testosterone and androstenedione)
Zona reticularis – It produces DHES or dehydroepiandrosterone (also called androstenolone)
2.Adrenal Medulla
The last and innermost part of the adrenal gland is the medulla. It contains the Chromaffin cells, which produce the body’s main source of catecholamines (such as adrenaline and noradrenaline) and endorphins. These are stored and released in response to stress.
Adrenal Gland Hormones
Epinephrine: Also called adrenaline, this hormone rapidly responds to stress by increasing the heart rate and raising blood glucose levels in the blood.
Norepinephrine: Also called noradrenaline, this hormone works with epinephrine in reacting to stress. Its primary function is to mobilize the body and brain for action.
Hydrocortisone: It is commonly known as cortisol or a steroid hormone. It is involved in regulating body functions like the conversion of fats, and carbohydrates to energy and also plays a vital role in other metabolic processes.
Corticosterone: This hormone works with hydrocortisone to control the immune response and prevents inflammatory reactions.
Adrenal Gland Disorders
Adrenal Gland disorders appear when not enough hormones or inadequate hormones are produced by the adrenal glands. Even abnormal growths or tumours can cause certain illness.
Cushing’s Syndrome is a condition where the cortisol levels in the body are very high. The cause can be a tumour in the adrenal gland or the pituitary gland.
Adrenocortical carcinoma is a cancerous tumour that usually develops in the outer layer of the adrenal gland. This type of tumour is typically found years after they have spread to other organs in the body.
Congenital Adrenal Hyperplasia (CAH) is a genetic disorder characterized by very low levels of cortisol production. The people inflicted with this condition may also have other hormonal imbalances where their bodies may make very little aldosterone, but too much androgen.
Addison’s Disease is caused when adrenal glands produce insufficient cortisol or aldosterone. It results in weakness, fatigue, low blood pressure, nausea, etc. In 70% of cases, Addison's disease is caused due to autoimmune disorder, where the body mistakenly attacks the adrenal glands. As a result, the adrenal gland does not produce the hormone aldosterone in sufficient quantities.