Blood is pumped at high pressures in arteries from the heart to ensure that all parts of the body receive adequate blood flow. Capillary beds, however, would hemorrhage under direct arterial pressures. How does the design of the circulation network contribute to reducing blood pressure to avoid this scenario?
A) Fluid loss from the arteries is high enough that pressure drops off significantly by the time blood reaches the capillaries.
B) Blood flow through the capillaries is essentially frictionless, and this reduces the amount of pressure on their walls.
C) The total cross- sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary, leading to a reduced blood pressure.
D) All of the above answers apply.

Question

Quizplus · Accepted Answer

The total cross-sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary. This leads to a reduced blood pressure, which is necessary to prevent damage to the delicate walls of the capillaries. Option A is incorrect because fluid loss from the arteries is not high enough to cause a significant drop in pressure. Option B is incorrect because blood flow through the capillaries is not frictionless, and there is still some pressure on their walls. Option D is incorrect because not all the answers apply.

Blood Is Pumped at High Pressures in Arteries from the Heart