Blood is transported through the venous system by means of:

(a) Skeletal muscle contractions

(b) Decreasing blood pressure

(c) The respiratory pump

(d) A and C

The most important factor in vascular resistance is:

(a) The viscosity of the blood

(b) The diameter of the lumen of blood vessels

(c) Turbulence due to irregular surfaces of blood vessels

(d) The length of the blood vessels

Which of the following conditions would have the greatest effect on peripheral resistance?

(a) Doubling the length of a vessel

(b) Doubling the diameter of a vessel

(c) Doubling the viscosity of the blood

(d) Doubling the turbulence of the blood

(e) Doubling the number of white cells in the blood

How do pressure and resistance affect cardiac output and peripheral blood flow?

How does the control of blood flow to the skin for the purpose of regulating body temperature differ from the control of nutrient blood flow to skin cells?

Which of the following factors would increase peripheral resistance?

a. Increased blood viscosity

b. Shorter vessel

c. Vasodilation

d. An increase in vessel radius

Explain the mechanisms that assist in the return of venous blood to the heart.

You are babysitting two children who are having a contest to see who can hang upside-down for the longest time. At the end of the contest, both children feel dizzy and are worried they are sick. Explain to them why they feel this way and why the effect is only temporary. (Hint: Consider how the baroreceptor reflex responds when a person hangs upside-down.)