The shutting of the semilunar valves occurs during which phase?
A.
Isovolumetric contraction
B.
Ventricular ejection
C.
Isovolumetric relaxation
D.
Atrial contraction and ventricular filling
E. Late ventricular diastole
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Question 2) Immediately prior to atrial contraction, blood continues to enter the atria from the venae cavae and pulmonary veins.
Indicate whether this statement is true or false.
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Question 3) Just prior to atrial contraction,
A. all four chambers are at rest and AV valves are open.
B. all four chambers are at rest and AV valves are closed.
C. all four chambers are contracting and all valves are open.
D. both ventricles are contracting and blood is being ejected into the major arteries.
E. both atria are contracting and blood is being ejected into the major arteries.
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Question 4) In an EKG, the P wave is generated when the
A. ventricles depolarize.
B. atria depolarize.
C. atria repolarize.
D. ventricles repolarize.
E. Purkinje fibers initiate an impulse.
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Question 5) During the S-T segment, what is occurring within cardiac muscle cells?
A. Sodium is rapidly diffusing out of atrial muscle cells.
B. Sodium channels are beginning to open in ventricular cells and calcium is entering through slow channels in atrial cells.
C. Calcium is entering and potassium is leaving ventricular cells.
D. Potassium is entering atrial cells and sodium is leaving ventricular cells.
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Question 6) Which segment of the ECG reflects the plateau phase of ventricular muscle cells' action potentials?
A. P-T segment
B. S-T segment
C. Q-R segment
D. P-R interval
E. T-P interval
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Question 7) What part of the cardiac conduction system is located in the posterior wall of the right atrium, adjacent to the entrance of the superior vena cava?
A. AV bundle
B. Bundle branches
C. Purkinje fibers
D. AV node
E. SA node
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Question 8) In an ECG, what does the T wave represent?
A. Depolarization of the atria
B. Depolarization of the right ventricle
C. Repolarization of the ventricles
D. Closure of the AV valves
E. Depolarization of the left ventricle
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Question 9) The atrioventricular (AV) node is located in the
A. floor of the left atrium.
B. floor of the right atrium.
C. roof of the left ventricle.
D. back wall of the right ventricle.
E. back wall of the left ventricle.
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Question 10) The plateau phase of an action potential
A. occurs only in skeletal muscle and makes those fibers' contractions most forceful.
B. leads to tetanic contractions in smooth and skeletal muscle.
C. allows cardiac muscle cells to contract and then relax without locking up.
D. allows cardiac muscle cells to exhibit synchronous fibrillation.
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