Emergency Medical Technician (EMT) Practice Test

What are the actions of nitroglycerin?

1. Increases heart rate, constricts blood vessels, decreases blood flow

2. Inhibits blood clotting, reduces pain, induces sleep

3. Smooth muscle relaxation, reduces cardiac workload, dilates coronary arteries, and dilates systemic arteries

4. Stimulates appetite, enhances memory, boosts energy levels

The correct answer is: Smooth muscle relaxation, reduces cardiac workload, dilates coronary arteries, and dilates systemic arteries

The actions of nitroglycerin primarily involve smooth muscle relaxation, which is crucial for its function as a vasodilator. By relaxing smooth muscle in blood vessels, nitroglycerin effectively dilates coronary arteries, thus increasing blood flow to the heart muscle. This is especially important for patients with angina, as it can alleviate chest pain caused by reduced blood flow. Additionally, nitroglycerin reduces overall cardiac workload by decreasing the resistance that the heart must work against (afterload). By dilating systemic arteries, it lowers systemic vascular resistance, which helps reduce the heart's oxygen demand. These combined effects make nitroglycerin an important medication for treating conditions like angina and heart failure, as they enhance coronary blood flow while relieving strain on the heart. The other options do not accurately describe the pharmacological effects of nitroglycerin, making them incorrect in this context. For example, the actions of increasing heart rate and constricting blood vessels would oppose the effects of nitroglycerin. Similarly, inhibiting blood clotting or stimulating appetite do not relate to nitroglycerin's intended effects.