Question

5
the respiratory and circulatory systems: mastery test
during a blood drive, shann noticed that the nurse punctured his vein to connect the tube for withdrawing blood. why is blood obtained through veins and not from arteries when collecting blood?
a. veins have lower blood pressure than arteries.
b. veins have fewer valves than arteries.
c. veins have a larger diameter than arteries.
d. veins have more tissue layers than arteries.
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Explanation:

Veins have lower blood pressure than arteries, which makes them safer and easier to puncture for blood collection—arterial blood pressure is high, which would cause rapid, hard-to-control bleeding. Veins also have more valves than arteries, a larger diameter, and fewer tissue layers, but these are not the primary reason they are used for blood draws.

Answer:

A. Veins have lower blood pressure than arteries.