Chapter 15: Alterations in Blood Flow

Chapter 15: Alterations in Blood Flow

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

MULTIPLE CHOICE
1. Which vessel normally demonstrates the most rapid blood flow?
a. An arteriole
b. A capillary
c. A venule
d. The vena cava
ANS: D
The vena cava has the most rapid rate of flow. Arterioles don’t offer the most rapid blood flow. Capillaries are composed of a single
thickness of endothelial cells attached to a protein network called the basement membrane and don’t offer the most rapid blood
flow. A venule begins where the arteriole ends and doesn’t offer the most rapid blood flow.
REF: Pg. 316
2. The movement of blood through the vascular system is opposed by the force of
a. viscosity.
b. the vessel length.
c. the vessel radius.
d. resistance.
ANS: D
The movement of blood through the vascular system is opposed by the force of resistance. Three determinants of resistance are
vessel length, vessel radius, and blood viscosity. Viscosity is the thickness of fluid and has an effect on resistance. The length of the
vessel does have an effect on the resistance. Vessel radius has an effect on resistance.
REF: Pg. 314
3. Which causes vasoconstriction?
a. Norepinephrine
b. Calcium channel blocker
c. -Adrenergic antagonist
d. Acetylcholine
ANS: A
The release of norepinephrine results in arterial vasoconstriction via receptors located on the vascular smooth muscle walls.
Calcium channel blockers produce vasodilation by interfering with calcium intake into the vascular smooth muscle cells.
-Adrenergic antagonists do not cause vasoconstriction. Acetylcholine does not have an effect on vasoconstriction.
REF: Pg. 318
4. When systemic vascular resistance is decreased, blood flow
a. increases.
b. decreases.
c. stays the same.
d. moves to the extremities.
ANS: B
When SVR is pathologically decreased, the blood is spread over a larger area and blood flow slows dramatically. Individual organs,
such as the kidney and brain, may not obtain sufficient blood flow to meet metabolic needs. Blood flow decreases in response to
decreases in vascular resistance. When SVR is pathologically decreased, the blood is spread over a larger area and blood flow slows
dramatically. Individual organs, such as the kidney and brain, may not obtain sufficient blood flow to meet metabolic needs. Blood
flow is not diverted to the extremities when systemic vascular resistance is decreased. However, the vital organs may not have
sufficient blood flow to maintain metabolic needs.
REF: Pg. 315
5. Blood flow is slow through capillaries because capillaries
a. are so far away from the heart.
b. have the largest total cross-sectional area.
c. are so narrow.
d. have no smooth muscle.
ANS: B
The increased cross-sectional area in the capillary bed results in a significant decrease in velocity compared to the arterial and
venous networks. Blood flow through the capillaries is not affected by the distance to the heart. Capillaries do have a diameter that
is very small, but they have spaces that permit constituents to pass in and out of the capillaries. In some tissues, one or two smooth
muscle cells form a precapillary sphincter that controls flow through the vessel.