Chapter 21 Which of the following will elevate the plateau of the cardiac

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Hall: Guyton and Hall Textbook of Medical Physiology, 12th Edition

Chapter 21: Muscle Blood Flow and Cardiac Output During Exercise; the Coronary

Circulation and Ischemic Heart Disease

Test Bank

1. Which of the following normally causes vasodilation of skeletal muscle arterioles during

exercise?

A. Decreased plasma osmolality

B. Decreased plasma nitric oxide concentration

C. Increased plasma potassium concentration

D. Decreased plasma adenosine concentration

E. Increased plasma histamine concentration

2. The majority of venous blood flow leaves the heart muscle through the:

A. Anterior cardiac veins

B. Azygos vein

C. Bronchial veins

D. Coronary sinus

E. Thebesian veins

3. A healthy 40-year-old man has been exercising maximally for 15 minutes. Which of the

following conditions is likely to be present?

A. Arteriolar resistance in the gastrointestinal bed is increased by 200%

B. Cerebral blood flow is decreased to 50% of normal

C. Heart rate is unchanged

D. Cardiac output is increased 5%

E. Right atrial pressure is increased to 10 mmHg

4. Which of the following is normally associated with an increased tendency for the heart to

fibrillate following a myocardial infarction?

A. Current of injury from ischemic cardiac muscle

B. Decreased extracellular potassium concentration

C. Decreased sympathetic stimulation

D. Increased extracellular sodium concentration

E. Decrease in cardiac volume

5. Which of the following vascular beds experiences the most vasoconstriction in a person

near the end of a five mile run?

A. Cerebral

B. Coronary

C. Exercising muscle

D. Intestinal

E. Skin

6. Which is usually the most important controller of coronary blood flow?

A. Adenosine

B. Bradykinin

C. Prostaglandins

D. Carbon dioxide

E. Potassium ions

7. The mass sympathetic discharge at the beginning of exercise causes which of the

following?

A. Decreased cerebral blood flow

B. Decreased coronary blood flow

C. Increased parasympathetic impulses to the heart

D. Reverse stress relaxation

E. Venoconstriction

8. Which of the following will elevate the plateau of the cardiac output curve?

A. Surgically opening the thoracic cage

B. Placing a patient on a mechanical ventilator

C. Cardiac tamponade

D. Increasing parasympathetic stimulation of the heart

E. Increasing sympathetic stimulation of the heart

9. Which of the following normally cause the cardiac output curve to shift to the right along

the right atrial pressure axis?

A. Decreasing intrapleural pressure to -6 mmHg

B. Increasing mean systemic filling pressure

C. Taking a patient off a mechanical ventilator and allowing normal respiration

D. Surgically opening the chest

E. Breathing against a negative pressure

Test Bank

21-3

10. Which of the following increase the risk of adverse cardiac events?

A. Decreased blood levels of LDL

B. Decreased blood levels of HDL

C. Female gender

D. Moderate hypotension

E. Decreased blood triglycerides

11. A 70-year-old man with a weight of 100 kg and a blood pressure of 160/90 has been told

by his doctor that he has angina pain caused by myocardial ischemia. Which of the

following treatments would be beneficial to this man?

A. Increased dietary calcium

B. Isometric exercise

C. Give a beta-1 receptor stimulator

D. Acetylcholine infusion

E. Nitroglycerin

12. During mild exertion a 70-year-old man experiences an ischemia-induced myocardial

infarction and dies from ventricular fibrillation. In this patient, which factor was most

likely to increase the tendency of the heart to fibrillate after the infarction?

A. Increased parasympathetic stimulation of the heart

B. A decrease in ventricular diameter

C. Low potassium concentration in the heart extracellular fluid

D. A more negative ventricular membrane potential

E. Current of injury from the damaged area