Which of the following is the correct sequence of structures that allows the normal sequence of excitation to progress through the heart?
A. Bundle of His - Purkinje fibres - AV node B. SA node - Purkinje fibres - AV node - Bundle of His C. Purkinje fibres - AV node - SA node - Bundle of His D. SA node - AV node - Bundle of His - Purkinje fibres E. Bundle of His - SA node - AV node - Purkinje fibres
The heart is a complex organ and consists of specialized connections that allow the heart to conduct the current for maximum excitation. These fibers have special names and are different from conventional heart muscle. The process goes from the SA node to the AV node and then to the Bundle of his and the Purkynje fibers to finally end in the heart muscle.
This special arrangement allows the heart to contract from below upwards so that the heart beats with maximum efficiency. The SA node is also considered as the pace maker of the heart which will allow a regular rhythm to establish so that the heart eats in a systematic manner.