Question 1

Which of the following best describes myogenic autoregulation in arterioles?

Accepted Answer

It is the ability of vascular smooth muscle to regulate its own contraction in response to changes in blood pressure.

Question 2

A patient is experiencing an allergic reaction, leading to widespread vasodilation. Which chemical is most likely responsible for this effect?

Accepted Answer

Histamine

Question 3

Which equation correctly represents the net pressure ($$P_{net}) $$determining the direction of bulk flow across capillaries?

Accepted Answer

$$P_{net} = P_H - \pi$$

Question 4

Which of the following statements about capillary exchange is correct?

Accepted Answer

Small dissolved solutes and gases move across capillary walls primarily by diffusion.

Question 5

During exercise, active hyperemia increases blood flow to skeletal muscles. What is the primary cause of this increase?

Accepted Answer

Accumulation of metabolic vasodilators in the extracellular fluid.

Question 6

Which vessel type has the thinnest walls and is most suited for exchange of materials between blood and tissues?

Accepted Answer

Capillaries

Question 7

If the hydrostatic pressure ($$P_H) at $$the arterial end of a capillary is 30 mm Hg and the colloid osmotic pressure ($$\pi) is 25 mm Hg$$, what is the net pressure ($$P_{net}) $$and the direction of fluid movement?

Accepted Answer

$$P_{net} = 5 mm Hg$$; net filtration out of capillary

Question 8

Which of the following is NOT a function of the lymphatic system?

Accepted Answer

Transporting oxygen directly to tissues

Question 9

A patient has edema due to inadequate lymph drainage. Which of the following best explains this condition?

Accepted Answer

Fluid accumulates in the interstitial space because lymphatic vessels fail to return it to circulation.

Question 10

Which neurotransmitter is primarily responsible for maintaining arteriolar tone via sympathetic innervation?

Accepted Answer

Norepinephrine

Question 11

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

Accepted Answer

Total cross-sectional area of capillaries is greatest.

Question 12

Which type of capillary is most commonly found in the bone marrow, liver, and spleen, and allows passage of large molecules?

Accepted Answer

Sinusoid

Question 13

Which hormone increases blood pressure by causing vasoconstriction and is released from the plasma?

Accepted Answer

Angiotensin II

Question 14

Which of the following mechanisms is responsible for the continuous (tonic) action potentials produced by baroreceptors?

Accepted Answer

Mechanical stretch of the carotid arteries and aorta

Question 15

Which of the following would most likely result in increased filtration at the arterial end of a capillary?

Accepted Answer

Increase in hydrostatic pressure ($$P_H)$$

Question 16

Which of the following is a paracrine signal that causes vasodilation?

Accepted Answer

Nitric oxide

Question 17

If a tissue experiences decreased blood flow for a period, which process restores normal flow when circulation resumes?

Accepted Answer

Reactive hyperemia

Question 18

Which of the following best describes the role of fenestrated capillaries?

Accepted Answer

They have large pores that allow rapid exchange of water and small solutes.

Question 19

Which of the following would most likely decrease the amount of fluid returned to the circulatory system by the lymphatic system?

Accepted Answer

Blockage of lymph vessels by parasites

Question 20

Which of the following is true regarding the distribution of blood to tissues?

Accepted Answer

Arterioles are arranged in parallel, allowing individual regulation of blood flow.

Vascular Resistance, Capillary Exchange, and the Lymphatic System

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