RAASjärjestelmässä

RAASjärjestelmässä, often referred to as the Renin-Angiotensin-Aldosterone System (RAAS), is a vital hormonal cascade that plays a crucial role in regulating blood pressure and fluid balance within the body. This complex system is activated when the body detects a drop in blood pressure or reduced blood flow to the kidneys.

The primary trigger for RAAS activation is the release of renin from the kidneys. Renin then acts on angiotensinogen, a protein produced by the liver, to form angiotensin I. This intermediate molecule is then converted to angiotensin II by an enzyme called angiotensin-converting enzyme (ACE), which is found primarily in the lungs.

Angiotensin II is a potent vasoconstrictor, meaning it narrows blood vessels, which directly increases blood pressure. It also stimulates the adrenal glands to release aldosterone. Aldosterone, in turn, acts on the kidneys, promoting the reabsorption of sodium and water. This increased sodium and water retention leads to a higher blood volume, further contributing to an elevation in blood pressure. Additionally, angiotensin II can stimulate the release of antidiuretic hormone (ADH), which also enhances water reabsorption by the kidneys.

The RAAS is a tightly regulated system. While essential for maintaining adequate blood pressure, its overactivation can contribute to various cardiovascular diseases, including hypertension and heart failure. Consequently, many medications used to treat these conditions target specific components of the RAAS, such as ACE inhibitors and angiotensin II receptor blockers.