Final answer:
Nitroglycerin works by releasing nitric oxide, which acts as a vasodilator to expand blood vessels, increases blood flow to the heart, and reduces myocardial oxygen demand. Therefore, the correct answer to its mechanism is all of the above: acting as a vasodilator, increasing blood flow to the heart, and reducing myocardial oxygen demand.
Step-by-step explanation:
The mechanism of nitroglycerin includes several actions that benefit the heart, especially during conditions like myocardial infarction (MI) or angina. Nitroglycerin primarily works by triggering the release of nitric oxide (NO), a potent vasodilator. This vasodilation effect causes the blood vessels to expand, thereby increasing blood flow to the heart and reducing the heart's oxygen demand because it decreases myocardial workload. Not only does nitroglycerin act as a vasodilator, but it also indirectly reduces blood pressure and enhances glomerular filtration. The release of nitric oxide upon nitroglycerin application relaxes the smooth muscle in the tunica media of coronary vessels, which is a key factor in providing therapeutic relief during a cardiac event. Given its varied effects on the cardiovascular system, the correct answer to the mechanism of nitroglycerin is that it encompasses all three actions mentioned: it acts as a vasodilator, it increases blood flow to the heart, and it reduces myocardial oxygen demand.