Figure 1.

The activation of systemic renin-angiotensin-aldosterone system cascade for blood pressure control. The activation of the circulating RAAS cascade that follows a blood pressure fall begins with renin secretion by the kidney. Once it has been released into the bloodstream, renin cleaves angiotensinogen to form Ang I, which is then converted to Ang II by pulmonary ACE. Ang II stimulates vasoconstriction, renal retention of salt and water, aldosterone secretion, and sympathetic activity, whereby it increases blood pressure. ACE is for angiotensin-converting enzyme; Ang is for angiotensin; RAAS is for renin-angiotensin-aldosterone system.