Question

List the sequence of action potential generation of the heart's intrinsic conduction system:

Answer 1

Our heart rate is always determined by the spontaneous action potential generation in the SA that is sinoatrial node and conduction in the AV that is atrioventricular node. It's the number of heartbeats over the course of a minute.

The conduction system of the heart. Left:Normal excitation originates in the sinoatrial node and it propagates through both Atria. The atrial depolarization spreads to the atrioventricular node. It then passes through of His to the bundle branches.The steps of intrinsic conduction are -

1) Impulse generation.

The SA contracts which generates nerve impulses which travel in the wall of the heart. The Atria contracts.

2) AV node impulse conduction.

When the impulses from the SA node reaches the AV node, there is a delay. During this delay period, the Atria contracts and empty it's contents to the ventricles.

3) AV Bundle Impulse Conduction .

After the 2nd step, the generated impulses are sent down the AV bundle.

4) Purkinje Fibres Impulse Conduction.

The AV bundles divides further into purkinje fibres. It the triggers the muscle fibres to contract. The left ventricle pumps blood to the aorta and the right ventricle sends blood to the lungs.