Question 1

Which of the following best describes the function of elastic arteries in the circulatory system?

Accepted Answer

They act as pressure reservoirs, expanding and recoiling to maintain continuous blood flow during the cardiac cycle.

Question 2

A patient with polycythemia (increased red blood cell count) is likely to experience which of the following changes in their circulatory system?

Accepted Answer

Increased blood viscosity and increased total peripheral resistance (TPR)

Question 3

Which type of capillary is most likely to be found in the liver and bone marrow, and what is its primary structural characteristic?

Accepted Answer

Sinusoidal capillary; large intercellular clefts and incomplete basement membrane

Question 4

If the radius of a blood vessel is reduced by half, how does the resistance to blood flow change according to Poiseuille’s Law?

Accepted Answer

Resistance increases by a factor of 16

Question 5

Which of the following equations correctly represents the relationship between mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR)?

Accepted Answer

$$MAP = CO 	imes TPR$$

Question 6

A patient stands up quickly and feels dizzy. Which reflex is primarily responsible for restoring their blood pressure to normal?

Accepted Answer

Baroreceptor reflex

Question 7

Which of the following best explains why veins are called capacitance vessels?

Accepted Answer

They can accommodate large volumes of blood at low pressure.

Question 8

During vigorous exercise, blood flow to skeletal muscles increases dramatically. Which mechanism is primarily responsible for this change?

Accepted Answer

Intrinsic metabolic autoregulation (active hyperemia)

Question 9

Which of the following statements about capillary beds is correct?

Accepted Answer

Vascular shunts allow blood to bypass true capillaries.

Question 10

A patient has a blood pressure of 120/80 mm Hg. What is their mean arterial pressure (MAP)?

Accepted Answer

$$MAP = 80 + \frac{1}{3}(120-80) = 93\ mm\ Hg$$

Question 11

Which of the following would most likely cause a decrease in mean arterial pressure (MAP)?

Accepted Answer

Decreased stroke volume

Question 12

Which adaptation helps return blood to the heart in the venous system, especially from the lower limbs?

Accepted Answer

Muscular pump action of skeletal muscles

Question 13

Which of the following best describes the effect of nitric oxide (NO) released by endothelial cells?

Accepted Answer

It causes vasodilation of arterioles.

Question 14

Which of the following is a correct statement about the baroreceptor reflex?

Accepted Answer

A rise in MAP inhibits the vasomotor center, leading to vasodilation and decreased MAP.

Question 15

Which of the following is the primary determinant of total peripheral resistance (TPR) in the systemic circulation?

Accepted Answer

Blood vessel diameter

Question 16

A patient with chronic hypertension is at risk for which of the following complications due to adaptation of baroreceptors?

Accepted Answer

Baroreceptors adapt to a higher set point, making them less effective at lowering blood pressure.

Question 17

Which of the following best explains why blood flow is lowest in the capillaries despite their small diameter?

Accepted Answer

The total cross-sectional area of all capillaries is very large, reducing velocity.

Question 18

Which hormone decreases mean arterial pressure (MAP) by causing vasodilation and promoting sodium excretion?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 19

Which of the following is a direct effect of angiotensin II in the regulation of blood pressure?

Accepted Answer

It acts as a potent vasoconstrictor, increasing total peripheral resistance (TPR).

Question 20

Which of the following best describes the difference between intrinsic and extrinsic controls of blood flow?

Accepted Answer

Intrinsic controls regulate blood flow to match local tissue needs, while extrinsic controls maintain systemic blood pressure.

Blood Vessel Structure, Function, and Circulatory Physiology

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