Co-ordination of Cardiac Cycle

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

• To pump blood through the heart

• To initiate the electrical signal for the heartbeat

• To prevent backflow of blood

• To increase blood pressure

Which part of the heart is responsible for delaying the electrical signal to ensure the ventricles fill with blood before contracting?

• Sinoatrial node (SAN)

• Atrioventricular (AV) node

• Bundle of His

• Purkinje fibres

What is the term used to describe the heart's ability to beat on its own without external stimulation?

• Neurogenic

• Myogenic

• Autogenic

• Cardiogenic

During which phase of the cardiac cycle do the atria contract?

• Atrial diastole

• Atrial systole

• Ventricular diastole

• Ventricular systole

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

• A layer of conductive tissue

• A layer of non-conductive tissue

• The Bundle of His

• The Purkinje fibres

Through which structure does the electrical activity pass to reach the ventricles?

• Sinoatrial node (SAN)

• Atrioventricular (AV) node

• Bundle of His

• Purkinje fibres

What is the role of Purkinje fibres in the cardiac cycle?

• To initiate the heartbeat

• To delay the electrical signal

• To conduct the electrical signal through the ventricles

• To prevent backflow of blood

How does the heart rate change during periods of exercise?

• It decreases

• It remains the same

• It increases

• It stops

Which part of the heart is known as the pacemaker?

• Atrioventricular (AV) node

• Sinoatrial node (SAN)

• Bundle of His

• Purkinje fibres

What is the sequence of electrical conduction in the heart?

• SAN → AV node → Purkinje fibres → Bundle of His

• AV node → SAN → Bundle of His → Purkinje fibres

• SAN → AV node → Bundle of His → Purkinje fibres

• Purkinje fibres → SAN → AV node → Bundle of His