Question

How does the blood pressure, blood velocity, and total cross-sectional area relate to the arteries, capillaries, and veins? How does this affect capillary function?

Answer 1

Blood pressure is the speed with which the blood exerts force against the arteries. Speed of the blood flow on the other hand is blood velocity. The total cross sectional area of indivdiual capillaries is low because of their small size, but the total cross sectional areas of the capillaries is high as the high branched formation means that there are many of them increasing the total area. The bvlood must move slowly in the capillaries to allow for diffusion as the capillaries are the only vessels with walls thick enough to diffuse. The blood velocity increases as it moves to the venules and veins. All these factors are closely interlinked with one another and determine the overall capillary function.