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Cardiac Muscle Physiology Quiz

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Which ion plays a crucial role in initiating the contraction of cardiac muscle cells?

Calcium (Ca2+)

Explanation

Ca2+ initiates muscle contraction.

What is the role of the sinoatrial (SA) node in the cardiac conduction system?

It initiates the electrical impulses for the heart's contraction.

Explanation

SA node starts heart's impulses.

What is the term for the volume of blood ejected by each ventricle during one contraction?

Stroke volume

Explanation

Stroke volume is blood ejected per contraction.

Which structure is responsible for conducting the electrical impulses from the atria to the ventricles in the heart?

Bundle of His

Explanation

Bundle of His conducts atria-ventricle impulses.

During the cardiac cycle, which phase corresponds to the simultaneous contraction of both atria?

Atrial systole

Explanation

Atrial systole is simultaneous atrial contraction.

What is the primary energy source for cardiac muscle contraction?

Fatty acids

Explanation

Fatty acids fuel muscle contraction.

Which neurotransmitter is released at the neuromuscular junction of the cardiac muscle?

Epinephrine

Explanation

Epinephrine is released.

Which of the following factors can increase myocardial oxygen demand?

Increased preload

Explanation

Increased preload ups oxygen demand.

During which phase of the cardiac action potential does calcium influx lead to muscle contraction?

Depolarization

Explanation

Calcium influx triggers depolarization.

#10

Which of the following is responsible for the long refractory period in cardiac muscle cells?

Potassium (K+)

Explanation

K+ causes long refractory period.

#11

What is the role of the Frank-Starling mechanism in the heart?

Adjustment of preload

Explanation

Frank-Starling adjusts preload.

#12

What is the primary function of troponin in cardiac muscle contraction?

Regulates the myosin-actin interaction.

Explanation

Troponin regulates muscle interaction.

#13

What is the term for the relaxation phase of the cardiac cycle when the heart chambers refill with blood?

Diastole

Explanation

Diastole is the relaxation phase.

#14

Which of the following hormones increases heart rate and force of contraction?

Epinephrine

Explanation

Epinephrine boosts heart activity.

#15

What is the primary function of the atrioventricular (AV) node in the cardiac conduction system?

To delay the transmission of electrical impulses.

Explanation

AV node delays impulses.

#16

Which of the following factors can increase the contractility of cardiac muscle?

Positive inotropic drugs

Explanation

Inotropic drugs boost contractility.

#17

Which of the following factors is known to decrease heart rate?

Parasympathetic stimulation

Explanation

Parasympathetic stimulation lowers heart rate.

#18

What is the term for the volume of blood in the ventricle at the end of diastole, just before contraction?

End-diastolic volume

Explanation

End-diastolic volume is blood volume pre-contraction.

#19

What is the primary factor determining the duration of the action potential in cardiac muscle cells?

Potassium (K+) efflux

Explanation

K+ efflux determines action potential duration.

Cardiac Muscle Physiology Quiz

Which ion plays a crucial role in initiating the contraction of cardiac muscle cells?

What is the role of the sinoatrial (SA) node in the cardiac conduction system?

What is the term for the volume of blood ejected by each ventricle during one contraction?

Which structure is responsible for conducting the electrical impulses from the atria to the ventricles in the heart?

During the cardiac cycle, which phase corresponds to the simultaneous contraction of both atria?

What is the primary energy source for cardiac muscle contraction?

Which neurotransmitter is released at the neuromuscular junction of the cardiac muscle?

Which of the following factors can increase myocardial oxygen demand?

During which phase of the cardiac action potential does calcium influx lead to muscle contraction?

Which of the following is responsible for the long refractory period in cardiac muscle cells?

What is the role of the Frank-Starling mechanism in the heart?

What is the primary function of troponin in cardiac muscle contraction?

What is the term for the relaxation phase of the cardiac cycle when the heart chambers refill with blood?

Which of the following hormones increases heart rate and force of contraction?

What is the primary function of the atrioventricular (AV) node in the cardiac conduction system?

Which of the following factors can increase the contractility of cardiac muscle?

Which of the following factors is known to decrease heart rate?

What is the term for the volume of blood in the ventricle at the end of diastole, just before contraction?

What is the primary factor determining the duration of the action potential in cardiac muscle cells?

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