Adrenal glands are triangle-shaped glands located on top of the kidneys. Each gland consists of a medulla (the center of the gland) which is surrounded by the cortex. The medulla is responsible for producing epinephrine and norepinephrine (adrenaline).
The adrenal cortex produces other hormones necessary for fluid and electrolyte (salt) balance in the body such as cortisone and aldosterone. The adrenal cortex is composed of three areas: @zona glomerulosa @zona fasciculata @zona reticularis
layer Name Primary productMost superficial Zona glumerulosa Mineralcorticoids cortical (e.g aldosterone) layer Middle corticol Zona fasciculata Glucocorticoids layer (e.g cartisol)Deepest cortical Zona reticularis Weak androgens layer (e.g adrenosterone)
Produced in the zona fasciculata. The primary glucocorticoid released by the adrenal gland in the human is cortisol and corticosterone in many other animals. Its secretion is regulated by the hormone ACTH from the anterior pituitary. Main: Cortisol (hydrocortisone)
Essential for life and metabolism Stress and circadian rhytm influences release of these hormone.
It stimulates the release of amino acids from the body It stimulates lipolysis, the breakdown of fat It stimulates gluconeogenesis, the production of glucose from newly- released amino acids and lipids
It increases blood glucose levels in response to stress, by inhibiting glucose uptake into muscle and fat cells It strengthens cardiac muscle contractions It increases water retention It has anti-inflammatory and anti-allergic effects
They are produced in the zona glomerulosa. The primary mineralocorticoid is aldosterone. Aldosterone is secreted in response - to high extracellular potassium levels - low extracellular sodium levels - low fluid levels and blood volume.
Aldosterone effect metabolism in 3 ways: 1)It increases urinary excretion of potassium ions 2)It increases interstitial levels of sodium ions 3)It increases water retention and blood volume
Renin Angiotensin System
The renin-angiotensin system (RAS) or the renin- angiotensin-aldosterone system (RAAS) is a hormone system that regulates blood pressure and water (fluid) balance. When blood volume is low, juxtaglomerular cells in the kidneys secrete renin Renin stimulates the production of angiotensin I, which is then converted to angiotensin II that causes blood vessels to constrict, resulting in increased blood pressure.
Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the tubules of the kidneys to increase the reabsorption of sodium and water into the blood. This increases the volume of fluid in the body, which also increases blood pressure.
They are produced in the zona reticularis. Androgens or androgenic steroids are produced by the zona reticularis layer of the adrenal cortex. Androgens, including testosterone are male sex hormones. It’s assist the development of male characteristics, and proper development of male sex organs during embryonic development.
There are usually three arteries that supply each adrenal gland: -The superior suprarenal artery is provided by the inferior phrenic artery -The middle suprarenal artery is provided by the abdominal aorta -The inferior suprarenal artery is provided by the renal artery
Venous drainage of the adrenal glands is achieved via the suprarenal veins: -The right suprarenal vein drains into the inferior vena cava -The left suprarenal vein drains into the left renal vein or the left inferior phrenic vein.