RAAS (renin-angiotensin-aldosterone system)

The renin-angiotensin-aldosterone system (RAAS) is a hormone system 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 chain reaction that produces angiotensin, which narrows blood vessels to raise pressure. It also prompts the adrenal glands to release aldosterone, which causes the kidneys to retain sodium and water, increasing blood volume. This coordinated response helps restore normal blood pressure and fluid levels in the body.