Nitric oxide (NO) acts as a vasodilator by:

A Blocking calcium channels

B Activating guanylyl cyclase to increase cGMP in vascular smooth muscle causing relaxation

C Inhibiting prostaglandins

D Increasing potassium channels

✓ Correct Answer: Option B

NO: produced by eNOS from L-arginine in endothelial cells. Diffuses to smooth muscle → activates soluble guanylyl cyclase → ↑cGMP → smooth muscle relaxation → vasodilation. Nitroglycerin releases NO.

💡 Why is B) the correct answer?

The correct answer to the question "Nitric oxide (NO) acts as a vasodilator by:" is Option B: Activating guanylyl cyclase to increase cGMP in vascular smooth muscle causing relaxation.

The other options — A) Blocking calcium channels, C) Inhibiting prostaglandins, D) Increasing potassium channels — are incorrect for this USMLE Exam Prep question. As explained above: NO: produced by eNOS from L-arginine in endothelial cells. Diffuses to smooth muscle → activates soluble guanylyl cyclase → ↑cGMP → smooth muscle relaxation → vasodilation. Nitroglycerin releases NO.

📚 About This USMLE Exam Prep Practice Question

This 3-level USMLE Exam Prep question from the Step 1 - Basic Sciences topic is part of BrainForge Quiz's free exam preparation library. Each question includes the correct answer and a detailed explanation to help you understand the underlying concept, not just memorize the answer.

How to use this page: Read the question above, consider all four options (A through D), then check the highlighted correct answer and explanation. For active timed practice, start a free USMLE Exam Prep practice test or use flashcards for spaced repetition review.

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Nitric oxide (NO) acts as a vasodilator by:

✓ Correct Answer: Option B

📚 About This USMLE Exam Prep Practice Question

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