Question 1

Which layer of a blood vessel is primarily responsible for vasoconstriction and vasodilation, and how does this affect blood pressure?

Accepted Answer

Tunica media; it contains smooth muscle that changes vessel diameter, directly affecting blood pressure.

Question 2

A patient’s blood pressure is measured at 135/85 mm Hg. What is their mean arterial pressure (MAP)? Use the formula $$MAP = 	ext{Diastolic Pressure} + \frac{1}{3}(	ext{Systolic Pressure} - 	ext{Diastolic Pressure}).$$

Accepted Answer

$$MAP = 85 + \frac{1}{3}(135 - 85) = 85 + \frac{1}{3}(50) = 85 + 16.7 = 101.7 mm Hg$$

Question 3

If the radius of a blood vessel doubles, what happens to the resistance to blood flow, assuming all other factors remain constant? Use the relationship $$R \propto \frac{1}{r^4$}.$$

Accepted Answer

Resistance decreases by a factor of 16.

Question 4

Which of the following best explains why blood flow velocity is slowest in the capillaries?

Accepted Answer

Capillaries have the largest total cross-sectional area, which slows velocity.

Question 5

A patient is experiencing edema due to increased capillary hydrostatic pressure. Which of the following best describes the mechanism?

Accepted Answer

Increased HPc pushes more fluid out of capillaries, overwhelming lymphatic drainage.

Question 6

Which hormone would most likely be elevated in a patient with chronic hypertension due to increased blood volume, and what is its effect?

Accepted Answer

Atrial natriuretic peptide (ANP); decreases blood volume by increasing salt and water loss.

Question 7

Which of the following equations correctly relates blood flow (F), pressure difference ($$\Delta P$$), and resistance (R)?

Accepted Answer

$$F = \Delta P / R$$

Question 8

A patient has a mutation that reduces plasma protein production. What is the most likely effect on capillary exchange?

Accepted Answer

Decreased capillary colloid osmotic pressure (OPc) leads to increased filtration and edema.

Question 9

Which of the following is a correct description of the process occurring at the arterial end of a capillary bed?

Accepted Answer

Net filtration occurs because hydrostatic pressure exceeds colloid osmotic pressure.

Question 10

Which of the following best describes the role of baroreceptors in blood pressure regulation?

Accepted Answer

They detect changes in blood pressure and send signals to the cardiovascular center in the medulla oblongata.

Question 11

A patient is hemorrhaging and you need to stop blood flow quickly. Which anatomical feature would you use to compress the artery and why?

Accepted Answer

A pressure point, because arteries are close to the body surface and can be compressed against bone.

Question 12

Which of the following is NOT a major source of resistance in the systemic circulation?

Accepted Answer

Heart rate

Question 13

Which of the following best explains why veins require valves while arteries do not?

Accepted Answer

Veins have lower pressure and need valves to prevent backflow of blood.

Question 14

Which of the following routes is used by lipid-soluble molecules to cross capillary walls?

Accepted Answer

Direct diffusion through endothelial membranes

Question 15

A patient’s arterioles constrict due to sympathetic stimulation. What is the expected effect on blood pressure and why?

Accepted Answer

Blood pressure increases because peripheral resistance increases.

Question 16

Which of the following best describes the effect of the muscular pump on venous return?

Accepted Answer

Contraction of skeletal muscles compresses veins, pushing blood toward the heart.

Question 17

Which of the following is the correct formula for net filtration pressure (NFP) at a capillary bed?

Accepted Answer

$$NFP = (HP_c + OP_{if}) - (HP_{if} + OP_c)$$

Question 18

Which of the following best explains why the pressure in veins is much lower than in arteries?

Accepted Answer

Energy is lost due to peripheral resistance as blood moves through the circulation.

Question 19

Which of the following would most likely result in increased reabsorption at the venous end of a capillary?

Accepted Answer

Increased capillary colloid osmotic pressure (OPc)

The Cardiovascular System: Blood Vessels and Circulation

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