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103) Depolarization of the atria corresponds to the ECG's A) P wave. B) QRS complex. D) T wave

A

100) Analyzing of the electrocardiogram can reveal all of the following except the B) stroke volume. C) condition of the conducting system. D) effects of drugs and poisons.

B

101) During the cardiac cycle, A) the P wave of the ECG occurs between the first and second heart sounds. B) the QRS complex of the ECG precedes the increase in ventricular pressure. C) the second heart sound occurs during atrial systole. .

B

111) Drugs that block the beta-one adrenergic receptors will B) decrease heart rate. C) increase contractility. D) increase cardiac output.

B

92) Pacemaker cells in the SA node B) generate action potentials that spread to the myocardium. C) are highly contractile. D) have an action potential identical to contractile cardiac muscle cells.

B

93) Which parts of the following statement are true? The AV node delivers the stimulus to the AV bundle, located within the interventricular septum. C) Both parts of the statement are true. D) Both parts of the statement are false.

C

97) The P wave of the electrocardiogram is a signal from B) depolarization of the AV node. C) depolarization of the atria. D) repolarization of the atria.

C

98) Depolarization of the ventricles is represented on an electrocardiogram by the C) S wave. D) QRS complex. E) PR complex.

D

99) The T wave on an ECG tracing represents C) ventricular depolarization. D) ventricular repolarization. E) ventricular contraction.

D

104) Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing. B) T wave C) QRS complex D) P-R interval

C

108) The heart is innervated by ________ nerves. B) sympathetic C) both parasympathetic and sympathetic D) neither parasympathetic nor sympathetic

C

105) If there is a complete block between the SA node and the AV node, how would the ECG be affected? C) There will be much bigger P waves. D) The ventricles will stop beating. E) The rate of P waves will be faster than the rate of QRS complexes.

E

94) If the pacemaker cells in the SA node become more permeable to potassium ions, C) the membrane will depolarize. D) the membrane will hyperpolarize. E) both heart rate will decrease and membrane will hyperpolarize.

E

102) During the T wave of the electrocardiogram, the ventricles are electrically ________ and functionally ________. A) depolarizing,; relaxing C) depolarizing; contracting D) repolarizing; relaxing

D

90) The following are structural components of the conducting system of the heart. 1. Purkinje fibers 2. AV bundle 3. AV node 4. SA node 5. bundle branches The sequence in which excitation would move through this system is which of the following? A) 1, 4, 3, 2, 5 B) 3, 2, 4, 5, 1 C) 3, 5, 4, 2, 1 D) 4, 3, 2, 5, 1 E) 4, 2, 3, 5, 1

D

110) Which of the following would decrease heart rate? C) increased levels of norepinephrine and/or epinephrine D) faster depolarization of the pacemaker potential E) increased parasympathetic stimulation of nodal fibers.

E

113) Acetylcholine slows the heart because it C) causes the pacemaker potential to depolarize more quickly. D) causes the pacemaker potential to depolarize more slowly. E) opens potassium ion channels in SA node cells and causes the pacemaker potential to depolarize more slowly.

E