Which organ’s function includes regulating blood pressure and blood volume through the renin-angiotensin system?

Which organ’s function includes regulating blood pressure and blood volume through the renin-angiotensin system?

• A. Kidneys
• B. Liver
• C. Heart
• D. Spleen

Answer: (A)

The kidney is the organ that regulates blood pressure and blood volume through the renin-angiotensin system. When renal perfusion or sodium delivery to the distal tubule falls, juxtaglomerular cells release renin. Renin converts angiotensinogen from the liver into angiotensin I, which is then converted to angiotensin II by ACE in the lungs. Angiotensin II causes vasoconstriction and stimulates aldosterone release from the adrenal cortex, increasing sodium and water reabsorption in the distal nephron and collecting ducts, thereby expanding blood volume and raising blood pressure. The kidneys can also adjust glomerular filtration by constricting efferent arterioles in response to angiotensin II, helping maintain GFR during hypotension. While the liver provides the precursor, and the heart or spleen don’t regulate this system directly, the kidney sits at the center of controlling BP and volume via RAAS.

The kidney is the organ that regulates blood pressure and blood volume through the renin-angiotensin system. When renal perfusion or sodium delivery to the distal tubule falls, juxtaglomerular cells release renin. Renin converts angiotensinogen from the liver into angiotensin I, which is then converted to angiotensin II by ACE in the lungs. Angiotensin II causes vasoconstriction and stimulates aldosterone release from the adrenal cortex, increasing sodium and water reabsorption in the distal nephron and collecting ducts, thereby expanding blood volume and raising blood pressure. The kidneys can also adjust glomerular filtration by constricting efferent arterioles in response to angiotensin II, helping maintain GFR during hypotension. While the liver provides the precursor, and the heart or spleen don’t regulate this system directly, the kidney sits at the center of controlling BP and volume via RAAS.