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Aldosterone release causes sodium and water retention, which causes increased blood volume, and a subsequent increase in blood pressure, which is sensed by the baroreceptors. [39] To maintain normal homeostasis these receptors also detect low blood pressure or low blood volume, causing aldosterone to be released.
The outermost layer, the zona glomerulosa is the main site for the production of aldosterone, a mineralocorticoid. The synthesis and secretion of aldosterone are mainly regulated by the renin–angiotensin–aldosterone system. The zona glomerulosa cells express a specific enzyme aldosterone synthase (also known as CYP11B2).
In the adrenal cortex, angiotensin II acts to cause the release of aldosterone. Aldosterone acts on the tubules (e.g., the distal convoluted tubules and the cortical collecting ducts) in the kidneys, causing them to reabsorb more sodium and water from the urine. This increases blood volume and, therefore, increases blood pressure.
Aldosterone acts on the kidneys to provide active reabsorption of sodium and an associated passive reabsorption of water, as well as the active secretion of potassium in the principal cells of the cortical collecting tubule and active secretion of protons via proton ATPases in the lumenal membrane of the intercalated cells of the collecting tubule.
Cells that will become adrenal tissue move retroperitoneally to the upper portion of the mesonephros. At seven weeks of gestation, the adrenal cells are joined by sympathetic cells that originate from the neural crest to form the adrenal medulla. At the end of the eighth week, the adrenal glands have been encapsulated and have formed a distinct ...
Schematic diagram of the renin–angiotensin–aldosterone system. Angiotensin II is a potent vasoconstrictor in a substrate concentration-dependent manner. [10] Angiotensin II binds to the type 1 angiotensin II receptor (AT1), which sets off a number of actions that result in vasoconstriction and therefore increased blood pressure.
The pituitary gland (or hypophysis) is an endocrine gland about the size of a pea and weighing 0.5 grams (0.018 oz) in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity (sella turcica) covered by a dural fold (diaphragma sellae).
The immune system specifically targets the cells of the adrenal cortex and destroys them, but Addison's disease can also be caused by a severe infection such as tuberculosis. Some symptoms include hypoglycemia and decreased blood sodium levels and increased blood potassium levels caused by a deficiency of aldosterone. These electrolyte ...