Question 1

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

Accepted Answer

Extrinsic control involves the sympathetic nervous system and hormones affecting blood flow throughout the body, while intrinsic control (autoregulation) involves local adjustments in arteriolar diameter to meet tissue needs.

Question 2

During vigorous exercise, which of the following changes occurs in the distribution of blood flow?

Accepted Answer

Blood flow to skeletal muscles increases due to intrinsic vasodilation, while extrinsic controls decrease blood flow to organs like the kidneys.

Question 3

Which of the following is a direct effect of increased tissue metabolic activity on local blood flow?

Accepted Answer

Increased levels of metabolic products (H$$^+$$, K$$^+$$, adenosine) cause vasodilation of arterioles.

Question 4

A patient has a mean arterial pressure (MAP) that suddenly increases above normal. What is the expected myogenic response in the arterioles supplying a tissue?

Accepted Answer

Arteriolar smooth muscle will constrict, decreasing blood flow to the tissue.

Question 5

Which of the following best explains why blood flow through the brain must remain constant?

Accepted Answer

Neurons are intolerant of ischemia, so constant blood flow is necessary to prevent loss of function.

Question 6

Which of the following equations correctly represents the calculation of Net Filtration Pressure (NFP) at a capillary bed?

Accepted Answer

$$NFP = (HP_c + OP_i) - (HP_i + OP_c)$$

Question 7

A patient with liver failure has a significant decrease in plasma protein concentration. What effect will this have on capillary exchange?

Accepted Answer

Capillary colloid osmotic pressure (OP$$_c) $$will decrease, resulting in more fluid remaining in the interstitial space and possible edema.

Question 8

Which of the following mechanisms is responsible for the movement of large molecules, such as proteins, across capillary walls?

Accepted Answer

Active transport via pinocytotic vesicles or caveolae

Question 9

In the pulmonary circuit, how does the local autoregulatory response to low O$$_2$$ levels differ from that in the systemic circuit?

Accepted Answer

Low O$$_2$$ causes vasoconstriction in the pulmonary circuit, directing blood to better-ventilated areas.

Question 10

Which of the following best describes the function of precapillary sphincters?

Accepted Answer

They regulate blood flow into true capillaries based on local chemical conditions.

Question 11

A person exposed to cold temperatures develops rosy cheeks. Which physiological mechanism best explains this phenomenon?

Accepted Answer

Constriction of superficial skin vessels traps blood in the vessels, causing a rosy appearance.

Question 12

Which of the following is true regarding blood flow velocity in the systemic circulation?

Accepted Answer

It is slowest in the capillaries, allowing time for exchange between blood and tissues.

Question 13

Which of the following is a function of blood flow through the skin?

Accepted Answer

Supplying nutrients to cells, regulating body temperature, and serving as a blood reservoir.

Question 14

During strenuous exercise, which mechanism allows the heart to receive more oxygen?

Accepted Answer

Coronary vessels dilate in response to local accumulation of vasodilators, increasing coronary blood flow.

Question 15

Which of the following statements about the hepatic portal system is correct?

Accepted Answer

It drains blood from the digestive organs and delivers it to the liver for processing before returning to the heart.

Question 16

Which of the following would most likely result in edema?

Accepted Answer

Increased capillary hydrostatic pressure (HP$$_c)$$

Question 17

Which of the following best describes the process of angiogenesis?

Accepted Answer

Long-term increase in the number and size of blood vessels to a region, often in response to chronic low oxygen.

Question 18

Which of the following is a correct route for the movement of water-soluble molecules across capillary walls?

Accepted Answer

Passage through intercellular clefts or fenestrations

Question 19

A patient experiences a MAP below 60 mm Hg. What is a likely consequence in the brain?

Accepted Answer

Syncope (fainting) may occur due to inadequate cerebral perfusion.

Ch.19 pt.2 Control of Blood Flow and Autoregulation in the Cardiovascular System

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