q4

[Anonymous]

Try to answer question above before reading answer and explanation below.



The correct answer is C. The same volume of blood flows through each of the different types of blood vessels each minute. Because the capillaries have the largest cross-sectional area (averaging 2500-5000 cm2), and because the velocity of blood flow is inversely related to cross-sectional area, it is clear that the mean linear velocity of a red blood cell is lowest in the capillaries. Under resting conditions, the mean linear velocity of a red blood cell in the capillaries is 0.3-0.6 mm/sec, whereas, the velocity in the aorta (choice A) is about 200 mm/sec. This low velocity of red blood cells in the capillary network allows plenty of time for oxygen to diffuse to the tissues.
The velocity of blood flow is ranked from highest to lowest as follows: aorta (choice A) > vena cavae (choice E) > large veins (choice E) > small arteries (choice D) > arterioles (choice B) > small veins (choice F) > venules (choice F) > capillaries. This ranking assumes the vena cavae have a larger cross-sectional area than the aorta; however, when the vena cavae are partially collapsed (which occurs often) they have a lower cross-sectional area and a higher velocity of blood flow compared to the aorta.

[Anonymous]

highest resistance has lowest velocity.i think artioler side of cappilary..
or is it arteriole only

[Anonymous]

is like when there's traffic on the four lanes hwy, the cars go really fast, unless there's an accidnet and they get reduced to just one lane. The result would be a trafficc jam, very, very slow...
now, the wider the hwy the faster you get home. And the opposite.
I know it doesnt sound scientific, is just to help you remember.