15/02/2026
The Renin-Angiotensin-Aldosterone System (RAAS) is a critical hormonal pathway that regulates blood pressure, blood volume, and electrolyte balance. Activated by reduced renal blood flow or low blood pressure, the kidneys release renin, initiating a cascade that produces angiotensin II, leading to vasoconstriction and aldosterone release.
Key Components and Mechanisms:
✔️Renin Release: Juxtaglomerular cells in the kidneys detect low blood pressure, low sodium, or sympathetic nerve activity and release renin.
✔️Activation Pathway: Renin converts angiotensinogen (from the liver) into Angiotensin I.
✔️ACE Conversion: Angiotensin-converting enzyme (ACE), primarily in the lungs, converts Angiotensin I into the highly active peptide, Angiotensin II.
✔️Angiotensin II Functions: A potent vasoconstrictor that increases blood pressure and stimulates the adrenal cortex to release aldosterone.
✔️Aldosterone Effect: Promotes sodium and water retention in the kidneys, increasing blood volume and raising blood pressure.
Clinical Significance:
⚡Hypertension & Heart Failure: An overactive RAAS is a major driver of hypertension, heart failure, and vascular remodeling.