Why is the velocity of blood flow the lowest in capillaries?
A)The capillary walls are not thin enough to allow oxygen to exchange with the cells.
B)Capillaries are far from the heart, and blood flow slows as distance from the heart increases.
C)The diastolic blood pressure is too low to deliver blood to the capillaries at a high flow rate.
D)The systemic capillaries are supplied by the left ventricle, which has a lower cardiac output than the right ventricle.
E)The total surface area of the capillaries is larger than the total surface area of the arterioles.

Question

Quizplus · Accepted Answer

The total surface area of the capillaries is much larger than the total surface area of the arterioles, allowing for a greater number of capillaries to exist. This results in lower blood flow velocity as the same volume of blood is distributed over a larger surface area. Additionally, the thin walls of capillaries and the presence of precapillary sphincters also contribute to slow blood flow velocity, facilitating the exchange of nutrients, gases, and waste products between the blood and tissues.

Why Is the Velocity of Blood Flow the Lowest in Capillaries