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The downward slope - Conduction of the heart - Ventricular conduction

6 important questions on The downward slope - Conduction of the heart - Ventricular conduction

What structures are involved in ventricular conduction?

the bundle of his:
- fibres which carry the impulse from the AVN to the bottom of the ventricle.
- carried to the bottom of the ventricle to ensure that the ventricle contracts from the bottom upwards- prevents the pressure of the ventricles rising and bursting.
- split into the right and left bundle branches
- further splits into smaller fibres called the perkunje fibres

Why is the transmission of the impulse down the bundle of his rapid?

- due to the high number of gap junctions between adjacent cells

What is the atrioventricular septum and what is its relevance?

provides electrical insulation between the atria and the ventricles
- ensures that the signal only travels down the bundle of his.
- a continuous fibrous barrier which separates the atrial muscle from the ventricular muscle.

How far do the perkunji fibres penetrate the cardiac muscle?

About a third of the way before they become continuous with the cardiac muscle.

Why does it take 0.06secs for the impulse to travel from the bundle to the most superficial ventricle muscle layer?

The cardiac muscle fibres are arranged around the heart in a spiral manner, with insulation between each spiralling layer. Therefore, the impulse cannot travel in a straight line, but rather follow the spiralling pattern. It therefore takes longer for the impulse to reach the most superficial muscle layer of the ventricles.

What is the importance of the perkunji fibres?

The rapid conduction of the impulse through the perkunji fibres ensures that all muscular parts of both ventricles contract at the same time. If this was not the case, the ventricular muscles would contract at different times and the pumping would be inefficient.