In the arterial system, blood moves primarily due to what surrounding pressure gradient?

• A. From high to low pressure
• B. From low to high pressure
• C. No gradient; pressure is uniform
• D. From pulsing pressure to continuous pressure

Answer: (A)

Blood flow in the arteries is driven by a pressure gradient: blood moves from areas of higher pressure to areas of lower pressure. The heart creates high arterial pressure during systole, and as blood travels away from the heart through the arterial tree, pressure falls along the way. This difference in pressure provides the driving force for flow (flow is proportional to the pressure difference divided by vascular resistance). If there were no gradient, or if pressure were lower downstream, there would be no net movement. While arterial pressure is pulsatile, the direction of flow follows the higher-to-lower pressure gradient rather than from pulsing to continuous pressure.