Question

question 13
veins are able to constrict and increase venous return because of their:
smooth muscle receiving parasympathetic impulses
smooth muscle receiving sympathetic impulses
valves receiving parasympathetic impulses
valves receiving sympathetic impulses
question 14
a blood pressure reading:
has either the systolic or diastolic value numerator, whichever is higher
has the systolic value in the numerator
none of these is always true
has the diastolic value in the numerator
question 15
identify the blood vessel entering or exiting the heart: inferior vena cava

Explanation:

For Question 13, veins constrict due to smooth - muscle receiving sympathetic impulses which increases venous return. For Question 14, a blood - pressure reading has the systolic value in the numerator and diastolic in the denominator.

Answer:

Question 13: smooth muscle receiving sympathetic impulses
Question 14: has the systolic value in the numerator