renin-angiotensin system

The renin-angiotensin system is a hormone process that helps regulate blood pressure and fluid balance. When blood pressure drops or sodium levels are low, the kidneys release an enzyme called renin. Renin triggers a series of reactions that produce angiotensin II, a powerful substance that constricts blood vessels, raising blood pressure. It also prompts the release of aldosterone, a hormone that signals the kidneys to retain sodium and water, increasing blood volume. Together, these actions help restore normal blood pressure and fluid levels.