When blood pressure , the kidneys release the enzyme renin i…
When blood pressure , the kidneys release the enzyme renin into the bloodstream. Renin breaks down from the liver into angiotensin I. Angiotensin I travels through the bloodstream and is then converted into angiotensin II by angiotensin-converting enzyme (ACE). Angiotensin II is an active hormone that causes the muscular walls of small arteries (arterioles) to constrict, leading to an in blood pressure. It also stimulates the adrenal glands to release and anti-diuretic hormones, causing retention of and excretion of potassium through urine, leading to water retention, increasing blood volume, and ultimately raising blood pressure.