Understanding the Cardiac Cycle

What is the primary function of the sinoatrial node (SA node) in the heart?

• To act as a barrier between the atria and ventricles

• To serve as the heart's pacemaker

• To conduct impulses directly to the ventricles

• To delay the wave of excitation

Where is the sinoatrial node (SA node) located?

• In the left ventricle

• In the right atrium

• In the left atrium

• In the right ventricle

What prevents the wave of excitation from passing directly from the atria to the ventricles?

• The bundle of His

• The Purkinje fibres

• A layer of non-conductive tissue

• The atrioventricular node

What is the role of the atrioventricular node (AV node) in the cardiac cycle?

• To initiate the heartbeat

• To delay the wave of excitation before it reaches the ventricles

• To contract the atria

• To directly stimulate the Purkinje fibres

Which structure is responsible for conducting the wave of excitation to the base of the ventricles?

• The sinoatrial node

• The atrioventricular node

• The bundle of His

• The Purkinje fibres

What is the function of the Purkinje fibres in the heart?

• To initiate atrial contraction

• To conduct the wave of excitation to all parts of the ventricles

• To delay the wave of excitation

• To act as a pacemaker

During which phase do the ventricles contract?

• Atrial systole

• Ventricular systole

• Diastole

• Atrial diastole

What happens during diastole in the cardiac cycle?

• The atria contract

• The ventricles contract

• The heart muscle relaxes

• The SA node fires

What ensures that blood is pushed upwards from the ventricles into the arteries?

• The contraction of the atria

• The upward branching of Purkinje fibres

• The delay at the AV node

• The non-conductive tissue layer

What is the nature of the heartbeat in terms of its origin?

• Neurogenic

• Myogenic

• Exogenic

• Endogenic