4. • Renin-Angiotensin System (RAAS)
• RAAS stands for “Renin-Angiotensin-Aldosterone
System,” which is a complex hormonal system in the
body that plays an important role in regulating blood
pressure, fluid and electrolyte balance, and kidney
function.
5. • The RAAS system involves a sequence of events that
begins with the production of renin by the kidneys.
• Renin acts on a protein called angiotensinogen, which
is produced by the liver, to convert it into angiotensin
I.
• Angiotensin I is then converted into angiotensin II by
an enzyme called angiotensin converting enzyme
(ACE), which is mainly produced in the lungs.
6. • Angiotensin II is a potent vasoconstrictor, which means it
narrows the blood vessels and raises blood pressure.
• It also stimulates the release of aldosterone from the
adrenal glands, which causes the kidneys to retain
sodium and water while excreting potassium.
• This helps to increase blood volume and maintain blood
pressure.
7. • The RAAS system is tightly regulated by various feedback mechanisms
to ensure that blood pressure and electrolyte balance are maintained
within a narrow range.
• Dysregulation of the RAAS system can lead to various medical
conditions such as hypertension, heart failure, and kidney disease.
• Therefore, drugs that target the RAAS system, such as ACE inhibitors
and angiotensin receptor blockers (ARBs), are commonly used to treat
these conditions.
