Cardiac Physiology Exam Quiz! MCQ
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The heart is the most important organ in the body and this being said as an aspiring cardiologist you are expected to ace your upcoming exam of cardio physiology to show just how attentive you have been in class and how equipped you are for the practice. Do give this block 3 cardio physiology part 1 exam and be better prepared for the finals
- 1.Which of the following normally has the most prominent prepotential?
- A.
Sinoatrial node
- B.
Atrial muscle cells
- C.
Bundle of His
- D.
Purkinje fibers
- E.
Ventricular muscle cells
- 2.Currents caused by the opening of which of the following channels contribute to the repolarization phase of the action potential of ventricular muscle fibers?
- A.
Na+ channels
- B.
Cl- channels
- C.
Ca2+ channels
- D.
K+ channels
- E.
HCO3- channels
- 3.In the sinoatrial (SA) node, phase 4 depolarization (pacemaker potential) is attributable to
- A.
An increase in K+ conductance
- B.
An increase in Na+ conductance
- C.
A decrease in C1- conductance
- D.
A decrease in Ca2+ conductance
- E.
Simultaneous increases in K+ and C1- conductances
- 4.During which phase of the ventricular action potential is the membrane potential closest to the K+ equilibrium potential?
- A.
Phase 0
- B.
Phase 1
- C.
Phase 2
- D.
Phase 3
- E.
Phase 4
- 5.During which phase of the ventricular action potential is the conductance to Ca2+ highest?
- A.
Phase 0
- B.
Phase 1
- C.
Phase 2
- D.
Phase 3
- E.
Phase 4
- 6.Which phase of the ventricular action potential coincides with diastole?
- A.
Phase 0
- B.
Phase 1
- C.
Phase 2
- D.
Phase 3
- E.
Phase 4
- 7.During which phase of the cardiac cycle does the mitral valve open?
- A.
Atrial systole
- B.
Isovolumetric ventricular contraction
- C.
Rapid ventricular ejection
- D.
Reduced ventricular ejection
- E.
Isovolumetric ventricular relaxation
- 8.The ventricles are completely depolarized during which isoelectric portion of the electrocardiogram (ECG)?
- A.
PR interval
- B.
QRS complex
- C.
QT interval
- D.
ST segment
- E.
T wave
- 9.Cardiac output of the right side of the heart is what percentage of the cardiac output of the left side of the heart?
- A.
25%
- B.
50%
- C.
75%
- D.
100%
- E.
125%
- 10.If the ejection fraction increases, there will be a decrease in
- A.
Cardiac output
- B.
End-diastolic volume
- C.
End-systolic volume
- D.
Heart rate
- E.
Pulse pressure
- 11.A ventricle has a volume of 100ml and an ejection fraction of 75%: If the heart rate is 70 beats/min, then cardiac output of this ventricle is closest to
- A.
3.45 L/min
- B.
4.55 L/min
- C.
5.25 L/min
- D.
8.00 L/min
- E.
9.85 L/min
- 12.The second heart sound is caused by
- A.
Closure of the aortic and pulmonary valves
- B.
Vibrations in the ventricular wall during systole
- C.
Ventricular filling
- D.
Closure of the mitral and tricuspid valves
- E.
Retrograde flow in the vena cava
- 13.The fourth heart sound is caused by
- A.
Closure of the aortic and pulmonary valves
- B.
Vibrations in the ventricular wall during systole
- C.
Ventricular filling
- D.
Closure of the mitral and tricuspid valves
- E.
Retrograde flow in the vena cava
- 14.Inspiration "splits" the second heart sound because
- A.
The aortic valve closes before the pulmonic valve
- B.
The pulmonic valve closes before the aortic valve
- C.
The mitral valve closes before the tricuspid valve
- D.
The tricuspid valve closes before the mitral valve
- E.
Filling of the ventricles has fast and slow components
- 15.During exercise, a man consumes 1.8 L of oxygen per minute. His arterial O2 content is 190 ml/L, and the O2 content of his mixed venous blood is 134 ml/L. His cardiac output is approximately
- A.
3.2 L/min
- B.
16 L/min
- C.
32 L/min
- D.
54 L/min
- E.
160 ml/min
- 16.The work performed by the left ventricle is substantially greater than that performed by the right ventricle, because in the left ventricle
- A.
The contraction is slower
- B.
The wall is thicker
- C.
The stroke volume is greater
- D.
The preload is greater
- E.
The afterload is greater
- 17.When a person moves from a supine position to a standing position, which of the following compensatory changes occurs?
- A.
Decreased heart rate
- B.
Increased contractility
- C.
Decreased total peripheral resistance (TPR)
- D.
Decreased cardiac output
- E.
Increased PR intervals
- 18.During exercise, total peripheral resistance (TPR) decreases because of the effect of
- A.
The sympathetic nervous system on splanchnic arterioles
- B.
The parasympathetic nervous system on skeletal muscle arterioles
- C.
Local metabolites on skeletal muscle arterioles
- D.
Local metabolites on cerebral arterioles
- E.
Histamine on skeletal muscle arterioles
- 19.The greatest pressure decrease in the circulation occurs across the arterioles because
- A.
They have the greatest surface area
- B.
They have the greatest cross-sectional area
- C.
The velocity of blood flow through them is the highest
- D.
The velocity of blood flow through them is the lowest
- E.
They have the greatest resistance
- 20.Pulse pressure is
- A.
The highest pressure measured in the arteries
- B.
The lowest pressure measured in the arteries
- C.
Measured only during diastole
- D.
Determined by stroke volume
- E.
Decreased when the capacitance of the arteries decreases
- 21.
- A.
Aorta
- B.
Central vein
- C.
Pulmonary artery
- D.
Right atrium
- E.
Renal artery
- 22.During which phase of the cardiac cycle is ventricular volume lowest?
- A.
Atrial systole
- B.
Isovolumetric ventricular contraction
- C.
Rapid ventricular ejection
- D.
Reduced ventricular ejection
- E.
Isovolumetric ventricular relaxation
- 23.The physiologic function of the relatively slow conduction through the atrioventricular node is to allow sufficient time for
- A.
Runoff of blood from the aorta to the arteries
- B.
Venous return to the atria
- C.
Filling of the ventricles
- D.
Contraction of the ventricles
- E.
Repolarization of the ventricles
- 24.Which of the following parameters is decreased during moderate exercise?
- A.
Arteriovenous O2 difference
- B.
Heart rate
- C.
Cardiac output
- D.
Pulse pressure
- E.
Total peripheral resistance (TPR)
- 25.Starling’s law of the heart.
- A.
Does not operate in the failing heart
- B.
Does not operate during exercise
- C.
Explains the increase in heart rate produced by exercise
- D.
Explains the increase in cardiac output that occurs when venous return is increased
- E.
Explains the increase in cardiac output when the sympathetic nerves supplying the heart are stimulated
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