Q.Define the following terms and give their location.
a. Purkinje fibre
b. Bundle of His

a. Purkinje fibres are the very fine fibres that arise from the right and left bundles of the AV bundle and spread throughout the ventricular muscle of their respective sides, carrying the impulse that triggers ventricular contraction.

b. The Bundle of His refers to the atrio-ventricular bundle (AV bundle) — the bundle of nodal fibres that runs from the AV node through the atrio-ventricular septa, emerges on top of the inter-ventricular septum, and there divides into a right and a left bundle. …

a. Purkinje fibre. These are very fine nodal fibres given off by the right and left bundles of the atrio-ventricular bundle. They spread throughout the ventricular muscle of their respective sides, delivering the electrical impulse directly into the working muscle of the ventricles and triggering their contraction. …

Method: Defining and Locating a Component of the Cardiac Conduction System

Use this approach for any "define and give the location" question about a structure in the heart's electrical conduction pathway.

Steps

Step 1: Place the structure on the conduction sequence

The cardiac conduction system fires and conducts an impulse in a fixed order: SA node -> AV node -> Bundle of His (AV bundle) -> right/left bundle branches -> Purkinje fibres. First identify where the asked-about structure sits in this chain.

Step 2: State its structural identity precisely

Give the structure's composition (e.g., "nodal fibres," "a bundle of the AV bundle's terminal branches") -- not just a one-word label -- since a full definition is being asked for.

Step 3: State the location in anatomical terms …