Cardiac Pharmacology: Difference between revisions

==Renin-Angiotensin-Aldosterone System==

The renin-angiotensin-aldosterone system (RAAS) is an important hormone-based pathway within the body that regulates fluid balance and thus systemic blood pressure. The system is activated by decreases in blood volume or pressure detected in two ways: a drop in blood pressure detected by baroreceptors (pressure sensors) located in the carotid sinus or a drop in flow rate through the kidneys, detected by the juxtaglomerular apparatus. The body responds to these stimuli to effect a restoration in blood pressure via the actions of three hormones; renin, angiotensin and aldosterone. Following the detected drop in blood pressure, the enzyme renin is released from specialised cells within the kidney. The substrate of renin is the inactive precursor of angiotensin I, angiotensinogen. Angiotensin I is then enzymatically converted by angiotensin converting enzyme (ACE) into angiotensin II, a hormone with various actions throughout the body that ultimately increase blood pressure, restoring fluid balance within the body.