what is renin angiotensin system
The reninâangiotensin system (RAS) or the reninâangiotensinâaldosterone system (RAAS) is a hormone system that regulates blood pressure and fluid balance.ngiotensin 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, while at the same time causing the excretion of potassium (to maintain electrochemical balance).