Question

- Predict the changes in BLOOD FLOW with each of the following conditions:

a. Vasoconstriction of the blood vessels in the skin

b. Vasodilation of the blood vessels to the stomach

c. Greatly increased hematocrit (this means extra red blood cells)

- True or False: Blood flow speed is slowest in veins due to their low driving pressures.

Thank you so much!

Answer 1

a. Vasoconstriction of the blood vessel in the skin leads to decreased blood flow to skin.

This occurs in cold ambient temperature to prevent heat loss.

b. Vasodilation of blood vessel of stomach leads to increased blood flow to stomach.

c. Greatly increased hematocrit decreses the blood flow. As Increased hematocrit Increases the viscosity of blood and hence decreses the flow.

TRUE - blood flow speed is slowest in the veins due to their low driving force.

Driving force is the difference of pressure between two ends of a vessel. Vein are compliant vessel with thin vessel wall and hence less pressure difference between the two ends of vein leading to low driving force.