Electrical System of the Heart

The electrical impulse that initiates a heartbeat is generated in which structure?

• Atrioventricular (AV) node

• Sinoatrial (SA) node

• Atria

• Ventricles

Which of the following is the correct sequence of the normal conduction pathway of the heart?

• AV node → SA node → Bundle of His → Purkinje fibers

• SA node → AV node → Bundle of His → Purkinje fibers

• Bundle of His →SA node → AV node → Purkinje fibers

• AV node → SA node → Purkinje fibers → Bundle of His

The PR interval on an electrocardiogram (ECG) represents the time taken for the electrical impulse to travel from the:

• SA node to the AV node

• AV node to the ventricles

• Atria to the ventricles

• Ventricles to the atria

The QRS complex on an ECG represents:

• Atrial depolarization

• Atrial repolarization

• Ventricular depolarization

• Ventricular repolarization

The T wave on an ECG represents:

• Atrial depolarization

• Atrial repolarization

• Ventricular depolarization

• Ventricular repolarization

Which structure is responsible for transmitting the electrical impulse from the atria to the ventricles?

• AV node

• SA node

• Bundle of His

• Purkinje fibers

The normal heart rate range is typically between:

• 40-60 beats per minute

• 60-100 beats per minute

• 100-160 beats per minute

• 160-200 beats per minute

Tags

NGSS.HS-LS1-3

Complete heart block occurs when:

• The SA node fails to fire

• The AV node fails to transmit the electrical impulse

• The ventricles contract before the atria

• There is a blockage in the coronary arteries

Which term describes the coordinated contraction of the atria followed by the ventricles?

• Diastole

• Systole

• Cardiac cycle

• Ventricular filling

Which property of conduction in the heart describes cardiac muscle cells' ability to respond to an electrical impulse?

• contractility
• conductivity
• excitability
• automaticity