New York State Emergency Medical Technician (EMT) Practice Exam

The systemic veins function by:

1. Returning deoxygenated blood back to the heart

2. Delivering oxygen-poor blood to the capillaries

3. Returning oxygen-rich blood back to the left atrium

4. Delivering deoxygenated blood to the capillaries

The correct answer is: Returning deoxygenated blood back to the heart

The systemic veins play a crucial role in the circulatory system by returning deoxygenated blood back to the heart, specifically to the right atrium. This process is essential for the proper functioning of the cardiovascular system, as it ensures that blood that has delivered oxygen to the body's tissues is efficiently returned to the heart for re-oxygenation in the lungs. The systemic veins collect this used (deoxygenated) blood from various parts of the body and transport it back, which is vital for maintaining circulation and preventing stagnation of blood flow. The other options refer to processes or functions that do not pertain to the role of systemic veins. For instance, delivering oxygen-poor blood to the capillaries is a function associated with arteries, specifically the pulmonary arteries which carry deoxygenated blood to the lungs, not the systemic veins. Similarly, returning oxygen-rich blood back to the left atrium is the function of the pulmonary veins, which carry oxygenated blood from the lungs to the heart. Delivering deoxygenated blood to the capillaries pertains to the arterial system as well, where oxygen-rich blood is pushed through to the tissues, and it does not accurately describe the function of the systemic veins in the context of blood circulation.