PATHOLOGY

Detailed explanation-1: -Typically, RAAS is activated when there is a drop in blood pressure (reduced blood volume) to increase water and electrolyte reabsorption in the kidney; which compensates for the drop in blood volume, thus increasing blood pressure.

Detailed explanation-2: -In particular, activation of the renin-angiotensin-aldosterone system (RAAS) leads to increased levels of angiotensin II and plasma aldosterone, and promote development of arterial vasoconstriction and remodeling, sodium retention, oxidative process, and cardiac fibrosis.

Detailed explanation-3: -Early in heart failure, RAAS is activated as a compensatory mechanism, but with the progression of the disease, it assumes a detrimental role, responsible for increased preload and afterload, which are the hallmarks of clinical heart failure syndrome.