Renin raises blood pressure by causing what?

• A. Vasodilation
• B. Vasoconstriction
• C. Increasing heart rate
• D. Decreasing renal perfusion

Answer: (B)

Renin raises blood pressure by initiating the renin-angiotensin-aldosterone system, which leads to vasoconstriction and increased blood volume. When renin is released, it converts angiotensinogen to angiotensin I, which is then turned into angiotensin II by ACE. Angiotensin II is a powerful vasoconstrictor, narrowing small arteries and raising systemic vascular resistance. It also stimulates aldosterone release from the adrenal glands, promoting sodium and water retention, which increases blood volume and further raises blood pressure.

Vasodilation would lower BP, not raise it. Increasing heart rate isn’t the direct effect of renin; it’s more about sympathetic activity. Decreasing renal perfusion is what triggers renin release, not an effect of renin on perfusion.