Renin Aldosterone Angiotensin

Renin-angiotensin-aldosterone system activates on low renal perfusion sensed by juxtaglomerular cells releasing renin converting angiotensinogen to angiotensin I, ACE in lungs to II potent vasoconstrictor raising pressure, stimulating aldosterone from adrenals retaining sodium and water expanding volume, also thirst and ADH for homeostasis.