Question

What is the route of conductance of electrical activity through the heart?

Answer 1

The human heart is myogenic in nature as it is capable of generating cardiac contractions through self exciting impulses independent of external neural input.

The heart beat results from electric depolarization (action potential) called cardiac impulse that originates in and is conducted to muscle fibres called purkinje fibres. These tracts are also known as nodal tissue or purkinje system.

The nodal tissue consists of sino-auricular node (SA node) , auriculoventricular node (AV node), bundle of His, right and left bundle branches and purkinje fibres.

The SA node acting as pacemaker on self excitation initiates a wave of contraction which spreads to both auricles. The musculatures of auricles and ventricles at not continuous and are separated by atrioventricular septum i.e. annular pads. The auricular contraction however stimulates AV node which further generates a new wave of contraction that passes over both ventricles simultaneously along the bundle of His and to right and left bundle branches alongwith. The contraction then passes to purkinje fibres of each ventricle.