Heart Flashcards

1
Q

Tetanic muscle contractions don’t occur in a normal cardiac muscle because
A) cardiac muscle tissue contracts on its own.
B) neural stimulation is lacking.
C) the refractory period lasts until the muscle relaxes.
D) the refractory period ends before the muscle reaches peak tension.
E) potassium channels outnumber sodium channels.

A

C) the refractory period lasts until the muscle relaxes.

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2
Q
When the semilunar valves close, the AV valves then 
A) close.  
B) open.  
C) make the third heart sound.  
D) contract.  
E) prolapse.
A

B) open.

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3
Q
The pulmonary semilunar valve prevents backward flow into the  
A) aorta.  
B) pulmonary trunk.  
C) pulmonary veins.  
D) right ventricle.  
E) left atrium.
A

D) right ventricle.

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4
Q
The \_\_\_\_\_\_\_\_ valve prevents backward flow into the left atrium. 
A) semicaval 
B) semilunar  
C) bicuspid  
D) tricuspid  
E) pulmonic
A

C) bicuspid

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5
Q

Compared to the right ventricle, the left ventricle has all the following characteristics, except that it
A) has a thicker wall.
B) is round in cross section.
C) pumps a greater volume.
D) works harder.
E) produces about four to six times more pressure when it contracts.

A

C) pumps a greater volume.

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6
Q

In cardiac muscle, the fast depolarization phase of the action potential is the result of
A) increased membrane permeability to sodium ions.
B) increased membrane permeability to potassium ions.
C) decreased membrane permeability to calcium ions.
D) decreased membrane permeability to sodium ions.
E) increased membrane permeability to chloride ions.

A

A) increased membrane permeability to sodium ions.

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7
Q

The long plateau phase of the cardiac muscle action potential is due to
A) movement of fewer sodium ions across the cell membrane.
B) calcium channels remaining open.
C) increased membrane permeability to potassium ion.
D) decrease in the amount of calcium diffusing across the membrane.
E) increased membrane permeability to sodium ions.

A

B) calcium channels remaining open.

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8
Q
The normal pacemaker of the heart is located in 
A) the Purkinje fibers.  
B) the sinoatrial node.  
C) the atrioventricular node.  
D) the wall of the left ventricle.  
E) both the left and right ventricles.
A

B) the sinoatrial node.

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9
Q
Abnormally slow depolarization of the ventricles would most  change the shape of the \_\_\_\_\_\_\_\_ in an ECG tracing.  
A) P wave  
B) T wave  
C) QRS complex  
D) P-R interval  
E) R-T interval
A

C) QRS complex

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10
Q
As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit  
A) tonus.  
B) treppe.  
C) tetany.  
D) recruitment.  
E) fatigue.
A

C) tetany.

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11
Q

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

A

E) heart rate will decrease and cells will hyperpolarize.

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12
Q

If the connection between the SA node and AV node becomes blocked,
A) the ventricles will beat faster.
B) the ventricles will beat more slowly.
C) the ventricular beat will remain unchanged.
D) cardiac output will increase.
E) the atria will contract more forcefully.

A

B) the ventricles will beat more slowly.

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13
Q

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  
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.
A

D) 4, 3, 2, 5, 1.

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14
Q
The P wave of the electrocardiogram is a signal from
A) depolarization of the SA node.
B) depolarization of the AV node.
C) depolarization of the atria.
D) repolarization of the atria.
E) depolarization of the ventricles.
A

C) depolarization of the atria.

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15
Q

If there is a complete block between the SA node and the AV node, how would the ECG be affected?
A) The P-R interval will be shorter.
B) The QRS duration will be longer.
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.

A

E) The rate of P waves will be faster than the rate of QRS complexes.

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16
Q
Depolarization of the ventricles is represented on an electrocardiogram by the  
A) P wave.  
B) T wave.  
C) S wave.  
D) QRS complex.  
E) PR complex.
A

D) QRS complex.

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17
Q
The T wave on an ECG tracing represents  
A) atrial depolarization.  
B) atrial repolarization.  
C) ventricular depolarization.  
D) ventricular repolarization.  
E) ventricular contraction.
A

D) ventricular repolarization.

18
Q

Analysis of the electrocardiogram can reveal all of the following, except the
A) heart rate.
B) stroke volume.
C) condition of the conducting system.
D) effects of drugs and poisons.
E) duration of the ventricular action potential.

A

B) stroke volume.

19
Q
During the T wave of the electrocardiogram, the ventricles are 
A) depolarizing.
B) repolarizing.
C) contracting.
D) relaxing.
E) both repolarizing and relaxing.
A

E) both repolarizing and relaxing.

20
Q

Pacemaker cells in the SA node
A) have a well-defined resting potential.
B) can spontaneously depolarize.
C) also contract with the rest of the cells in the heart wall.
D) are special neurons that convey signals from the brain to the heart.
E) All of the answers are correct.

A

B) can spontaneously depolarize.

21
Q
Depolarization of the atria corresponds to the EKG's 
A) P wave.  
B) QRS complex.  
C) QT interval.  
D) T wave.  
E) S-T segment.
A

A) P wave.

22
Q
The first heart sound is heard when the  
A) AV valves open.  
B) AV valves close.  
C) semilunar valves close.  
D) atria contract.  
E) blood enters the aorta.
A

B) AV valves close.

23
Q

The first heart sound (“lub”)
A) is associated with atrial systole.
B) is associated with closing of the mitral valve.
C) is associated with opening of the mitral valve.
D) is associated with closing of the aortic valve.
E) is associated with opening of the aortic valve

A

B) is associated with closing of the mitral valve.

24
Q

Considering the left ventricle, why does isovolumetric ventricular contraction occur during ventricular systole?
A) The ventricle needs to pressurize the blood to close the aortic valve.
B) Ventricular pressure is greater than atrial pressure so the ventricle cannot eject blood.
C) The bicuspid valve needs time to shut before the ventricle can eject blood.
D) Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve.
E) The ventricle is still filling with blood and therefore cannot eject blood during this time.

A

D) Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve.

25
Q
The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the
A) atrial systole.
B) early diastolic filling phase.
C) late diastolic filling phase.
D) systolic ejection phase.
E) dicrotic phase.
A

D) systolic ejection phase.

26
Q
A heart murmur might be caused by
A) aortic valve insufficiency.
B) mitral valve insufficiency.
C) pulmonic valve insufficiency.
D) swirling of blood in the ventricle.
E) All of the answers are correct.
A

E) All of the answers are correct.

27
Q

During ventricular systole, the
A) atria are contracting.
B) blood is entering the ventricles.
C) AV valves are closed.
D) pressure in the ventricles remains constant.
E) pressure in the aorta remains constant.

A

C) AV valves are closed.

28
Q
With each ventricular systole, 
A) blood pressure remains steady. 
B) the ventricles fill with blood. 
C) blood pressure decreases. 
D) cardiac output decreases. 
E) blood pressure increases.
A

E) blood pressure increases.

29
Q

An increase in the rate of action potentials from baroreceptors will trigger a reflex to
A) increase in heart rate.
B) decrease in heart rate.
C) decrease in blood pressure.
D) both decrease heart rate and decrease pressure.
E) both increase heart rate and increase pressure.

A

D) both decrease heart rate and decrease pressure.

30
Q
The volume of blood ejected from each ventricle during a contraction is called the  
A) end-diastolic volume.  
B) end-systolic volume.  
C) stroke volume.  
D) cardiac output.  
E) cardiac reserve.
A

C) stroke volume.

31
Q

Each of the following factors will increase cardiac output, except
A) increased venous return.
B) increased parasympathetic stimulation.
C) increased sympathetic stimulation.
D) increased heart rate.
E) increased force of contraction.

A

B) increased parasympathetic stimulation.

32
Q

Which of the following would increase heart rate?
A) increased sympathetic stimulation of SA node
B) decreased parasympathetic stimulation of nodal fibers
C) increased levels of epinephrine
D) faster depolarization of the pacemaker potential
E) All of the answers are correct.

A

E) All of the answers are correct.

33
Q

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

A

C) both parasympathetic and sympathetic

34
Q

Stroke volume depends on
A) end diastolic volume.
B) the contractility of the ventricle.
C) the pressure required to pump blood into the aorta.
D) venous return of blood to the heart.
E) All of the answers are correct.

A

E) All of the answers are correct.

35
Q
Cardiac output can be increased by all of the following except one. Choose the exception.
A) decreasing ejection fraction
B) decreasing end systolic volume
C) increasing stroke volume
D) increasing ejection fraction
E) increasing heart rate
A

A) decreasing ejection fraction

36
Q

Drugs known as calcium channel blockers such as nifedipine can be used to
A) decrease the force of cardiac contraction.
B) decrease blood pressure.
C) dilate the coronary arteries.
D) produce a negative inotropic effect.
E) All of the answers are correct.

A

E) All of the answers are correct.

37
Q

The cardioacceleratory center activates sympathetic neurons and the cardioinhibitory center controls parasympathetic neurons.
A) The first part of the statement is true but the second part is false.
B) The first part of the statement is false but the second part is true.
C) Both parts of the statement are true.
D) Both parts of the statement are false.
E) Both parts of the statement are true and relate to brainstem control of heart rate.

A

E) Both parts of the statement are true and relate to brainstem control of heart rate.

38
Q

Which of these is true about the atrial reflex?
A) also called Bainbridge reflex
B) triggered by atrial mechanoreceptors
C) triggered by increasing venous return
D) depends on sympathetic innervation
E) All of the answers are correct

A

E) All of the answers are correct

39
Q

Which of these would cause stroke volume to increase?
A) when venous return is decreased
B) when ventricular contraction is reduced
C) when diastolic blood pressure is decreased
D) decrease in heart rate
E) All of the answers are correct.

A

C) when diastolic blood pressure is decreased

40
Q
Cardiac output is increased by  
A) sympathetic stimulation.  
B) increased end systolic volume.
C) decreased end diastolic volume.
D) decreased venous return.
E) inhibiting the atrial reflex.
A

A) sympathetic stimulation.

41
Q
If the force of ventricular contraction increases, what will happen to the end-systolic volume? 
A) increase 
B) fluctuate rapidly 
C) remain the same 
D) decrease 
E) reduced to zero
A

D) decrease

42
Q

End-systolic volume is defined as the:
A) amount of blood a ventricle ejects per cycle
B) amount of blood which backflows into a ventricle
C) amount of blood remaining in an atrium after atrial systole
D) amount of blood remaining in a ventricle after contraction
E) stroke volume multiplied by the heart rate

A

D) amount of blood remaining in a ventricle after contraction