What is the primary effect of angiotensin II in the body?

The primary effect of angiotensin II in the body is that it causes vasoconstriction and stimulates aldosterone secretion. Angiotensin II is a potent vasoconstrictor, meaning it narrows blood vessels, which leads to an increase in blood pressure. This is part of the body's mechanism to regulate blood pressure and maintain blood flow to vital organs.

In addition to its vasoconstrictive properties, angiotensin II also promotes the secretion of aldosterone from the adrenal glands. Aldosterone is a hormone that acts on the kidneys to increase sodium and water retention, further increasing blood volume and blood pressure. By combining these two actions—vasoconstriction and stimulation of aldosterone secretion—angiotensin II plays a crucial role in the renin-angiotensin-aldosterone system (RAAS), which is essential for regulating cardiovascular function and fluid balance in the body.