Nitroglycerin administered for cardiac chest pain acts mainly to:

Nitroglycerin administered for cardiac chest pain acts mainly to:

• A. Relaxes the walls of the coronary arteries
• B. Increases heart rate
• C. Constricts peripheral arteries
• D. Slows respiration

Answer: (A)

Nitroglycerin relieves cardiac chest pain by causing vasodilation through the release of nitric oxide, which relaxes smooth muscle in the vessel walls. This dilation lowers the heart’s workload by reducing preload (venous return) and, to some extent, afterload, thereby decreasing myocardial oxygen demand. It can also widen the coronary arteries, improving blood flow to ischemic heart muscle. Because of these vasodilatory effects on the coronary arteries and overall reduction in oxygen demand, the action described—relaxing the walls of the coronary arteries—best explains how nitroglycerin helps relieve angina. It does not primarily act by increasing heart rate, constricting peripheral arteries, or slowing respiration.

Nitroglycerin relieves cardiac chest pain by causing vasodilation through the release of nitric oxide, which relaxes smooth muscle in the vessel walls. This dilation lowers the heart’s workload by reducing preload (venous return) and, to some extent, afterload, thereby decreasing myocardial oxygen demand. It can also widen the coronary arteries, improving blood flow to ischemic heart muscle. Because of these vasodilatory effects on the coronary arteries and overall reduction in oxygen demand, the action described—relaxing the walls of the coronary arteries—best explains how nitroglycerin helps relieve angina. It does not primarily act by increasing heart rate, constricting peripheral arteries, or slowing respiration.