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Chapter 18. Toxic Responses of the Heart and Vascular System

In which of the following locations would one NOT find spontaneous depolarization?

a. SA node.

b. myocardium.

c. AV node.

d. bundle of His.

e. Purkinje fibers.

Which of the following scenarios would increase contractility of the myocardium?

a. increased activity of the Na+/K+-ATPase.

b. increased activity of sacroplasmic reticulum Ca2+ ATPase.

c. decreased activity of sacroplasmic reticulum Ca2+ ATPase.

d. decreased intracellular calcium levels.

e. increased intracellular K+ levels.

All of the following statements regarding abnormal cardiac function are true EXCEPT:

a. Ventricular arrhythmias are generally more severe than atrial arrhythmias.

b. Ventricular hypertrophy is a common cause of ventricular arrhythmias.

c. Coronary artery atherosclerosis is a major cause of ischemic heart disease.

d. Right-sided heart failure results in pulmonary edema.

e. Tachycardia is classified as a rapid resting heart rate (>100 beats/min).

Ion balance is very important in maintaining a normal cardiac rhythm. Which of the following statements is TRUE?

a. Blockade of K+ channels decreases the duration of the action potential.

b. Blockade of Ca2+ channels has a positive inotropic effect.

c. Inhibition of Na+ channels increases conduction velocity.

d. Blockage of the Na+/K+-ATPase increases contractility.

e. Calcium is transported into the cell via a Ca2+-ATPase.

Which of the following is most likely NOT a cause of myocardial reperfusion injury?

a. cellular pH fluctuations.

b. damage to the sarcolemma.

c. generation of toxic oxygen radicals.

d. Ca2+ overload.

e. inhibition of the electron transport chain.

Which of the following statements regarding the cardiotoxic manifestations of ethanol consumption is FALSE?

a. Acute ethanol toxicity causes decreased conductivity.

b. Chronic alcohol consumption is associated with arrhythmias.

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