Overview Introduction The renin-angiotensin-aldosterone system (RAAS) attempts to maintain arterial blood pressure by controlling blood volume a decrease in arterial blood pressure is sensed by the kidneys as decreased renal perfusion pressure this in turn stimulates the juxtaglomerular cells to secrete renin into circulation login to view 3 more bullets note that a decrease in Na+ delivery to the macula densa also stimulates RAAS angiotensin II activates type I G protein-coupled angiotensin II receptors (AT1) receptors which acts on the adrenal cortex (zona glomerulosa) to increase aldosterone secretion login to view 2 more bullets directly stimulates the Na+-H+ exchange acts on the hypothalamus to increase thirst and the pituitary to increase anti-diuretic hormone (ADH) secretion login to view 2 more bullets acts on arterioles to increase total peripheral resistance and thus increasing arterial pressure preferrentially constricts the efferent arteriole to maintain glomerular filtration rate (GFR) in low volume states (e.g., hemorrhaging)