The human body’s Renin-Angiotensin Aldosterone System (RAAS) regulates blood pressure and fluid balances. When a person’s blood pressure or water levels drop, the body’s baroreceptors identify the drop, as do cells in the kidneys, which are responsible for releasing rennin into the body. In the case of a decline in blood pressure, the enzyme Renin transforms angiotensinogen to angiotensin I. Angiotensinogen is a protein in the liver, and, essentially, a chain-reaction process gets under way in which the body’s RAAS acts like a line of dominoes responding to the drop in low blood pressure: the kidney gets the chain reaction underway first, by releasing Renin. Renin converts the protein in the liver to the hormone angiotensin I. Angiotensin I is then converted by an enzyme in the lungs, which is called the angiotensin-converting enzyme (Angiotensin I is transformed into Angiotensin II). So kidneys, liver and lungs all work together in the initial stages of the body’s response to a drop in blood pressure. Angiotensin II raises the blood pressure in the body to counteract the drop and it does so by tightening the blood vessels. The narrower the blood vessels become, the greater the pressure on the blood stream grows. By constricting the...

The amount of water in the body has to be regulated. When the balanced fluid levels drop, the kidney responds by activating the RAAS. In the case of restoring fluid balance, the RAAS is triggered by the juxtaglomerular apparatus. The renal tubules begin to take in water and salt via the body’s urine supply, and potassium is traded for sodium. Aldosterone is released by the adrenal cortex, activated by the RAAS, and the aldosterone assists in the body’s absorption of sodium ions. In order to facilitate water absorption, the body releases the anti-diuretic hormone vasopressin, which assists in opening aquaporin channels. Recent studies have shown that the anti-diuretic hormone “can be synthesized in the heart to act locally in a cardiac paracrine [anti-diuretic] system prior to release into effluent vessels, where it is predicted to act systemically” (Wasilewski et al., 2016, p. 226).
When a patient experiences heart failure, the body does not receive the needed oxygen in the blood as blood…