MCQ CVS Flashcards
1. Which of the following is NOT an inward current? A. I Na B. I Ca C. I f D. I Na-K (pump)
C
7. Which of the following is a CORRECT order of blood flow through the heart? 1 - right atrium 2 - left atrium 3 - right ventricle 4 - left ventricle 5 - vena cava 6 - pulmonary artery 7 - pulmonary vein 8 - tricuspid AV valve 9 - bicuspid (mitral) AV valve 10 - pulmonary valve 11 - aortic valve 12 - aorta
A. 5, 1, 9, 3, 10, 6, 7, 2, 8, 4, 11, 12
B. 5, 1, 8, 3, 10, 7, 6, 2, 9, 4, 11, 12
C. 5, 1, 8, 3, 10, 6, 7, 2, 9, 4, 11, 12
D. 5, 1, 8, 3, 11, 6, 7, 2, 9, 4, 10, 12
c
9. Which of the following is NOT a part of the specialized conduction system of the heart? A. Cells of the SA node. B. Cells of the AV node. C. Working myocardial cells. D. His bundle. E. Purkinje fibers.
C
- Which of the following is INCORRECT concerning cardiac muscle?
A. Cardiac cells are smaller than skeletal muscle cells.
B. Electrical communication between cardiac cells is maintained via gap junctions which are specialized portions of the intercalated discs.
C. Mechanical attachment of cardiac cells is at the intercalated disc.
D. The spread of excitation through the heart muscle is 3-dimensional.
E. Transverse tubules are larger in skeletal muscle than in heart muscle allowing more diffusion of Ca2+ into the interior of the cell.
E
11. Which of the following is usually the dominant pacemaker and fires the fastest? A. SA node. B. AV node C. His bundle. D. Purkinje fibers.
A
Which of the following is NOT true of the parasympathetic control of the heart?
A. It affects muscarinic receptors.
B. It decreases heart rate via the SA node.
C. It decreases conduction velocity via the AV node.
D. It can be blocked by beta blockers, e.g. propranolol.
D
Which of the following is a TRUE statement concerning pacemaker potential?
A. Specialized cells depolarize during phase 4, but ventricular and atrial muscle cells do not.
B. Specialized cells depolarize during phase 3, but ventricular and atrial muscle cells do not.
C. Specialized cells repolarize during phase 4, but ventricular and atrial muscle cells do not.
D. Specialized cells repolarize during phase 3, but ventricular and atrial muscle cells do not.
E. None are correct
A
Which of the following is INCORRECT concerning the voltage clamp technique?
A. The voltage clamp technique is used to record action potentials from heart cells
B. It is useful to measure effects of antiarrhythmic agents on specific ion channels.
C. The voltage clamp can be used to set the Vm either for a segment of the cell membrane or the entire cell.
D. It allows the investigator to measure both the magnitude and time course of the ionic current generated by ions moving through channels.
A
Which of the following is the property of a cardiac cell to initiate and fire an action potential on its own without external stimulation? A. Selectivity B. Spontaneity. C. Automaticity. D. Conductance.
C
Which of the following does NOT show rapid initial depolarization at the start of an action potential? A. SA node. B. Atrial muscle. C. Purkinje fibers. D. Ventricular muscle. E. Bundle of His.
A
Sodium enters the cell during the upstroke of the action potential. What is the major mechanism for removing Na from the cell?
A. It passively diffuses out of the cell.
B. It is extruded via an ATP-dependent Na-K pump.
C. It is extruded via an ATP-dependent Na-Ca pump.
D. It is extruded via an ATP-independent Na-K pump.
E. It is extruded via an ATP-independent Na-Ca pump.
b
If sodium channels are open, membrane potential is +110 mV, and the equilibrium potential is +68 mV, how will sodium ions respond? A. They will move into the cell. B. They will move out of the cell. C. They will not move. D. The conductance will drop to zero.
B
Which of the following is NOT true of an inward ionic current?
A. It is negative.
B. It reduces the polarity of the cell.
C. It makes the membrane potential more negative.
D. It can be caused by Na ions moving into the cell
E. It can be caused by anions moving out of the cell.
C
If you reduced the outward current in a heart cell, what would be the result?
A. Increase the rate of repolarization.
B. Prolong the action potential.
C. Increase the rate of depolarization
B
Which of the following is INCORRECT concerning diastolic depolarization at the SA node?
A. It results from a decrease in IK.
B. Results from the activation of If carried mainly by Na ions.
C. Its rate is decreased by sympathetic stimulation.
D. Activating IKACh decreases its rate.
E. Its rate is decreased by decreasing ICa
C
If the heart rate increases, which of the following would be a result?
A. ERP would increase while APD would decrease.
B. ERP would decrease while APD would increase.
C. Both ERP and APD would increase.
D. Both ERP and APD would decrease.
D