PHGY 214 Lecture Notes - Lecture 2: Macula Densa, Angiotensin-Converting Enzyme, Afferent Arterioles
Document Summary
Baer topic 5: control of fluid balance: describe steps of renin-angiotensin-aldosterone pathway. Renin is secreted by the granular cells of the juxtaglomerular apparatus in response to a fall in nacl/ ecf volume or blood pressure. If nacl levels fall, the macula densa cell trigger granular cells to release more. Renin: increased sympathetic activity as a result of a drop in blood pressure stimulates the granular cells to secrete more renin. How does it work: once secreted into the blood renin acts as an enzyme to activate angiotensinogen (inactive) to angiotensin 1. Angiotensinogen is synthesized by the liver and is always present in blood plasma: when it passes through the pulmonary circulation of the lungs, angiotensin 1 is converted to. Angiotensin 2 by angiotensin converting enzyme (ace): angiotensin 2 stimulates the secretion of aldosterone from the adrenal cortex. Na+ reabsorption by the distal and collecting tubules. Na/k atp pump is on the basolateral surface of the principal cell (where blood is).
