Cardiac conduction

what is Conduction of action potential through the heart

The process of electrical signal transmission in the heart, starting from the sinoatrial node, passing through the atria, atrioventricular node, bundle branches, Purkinje fibers, and finally reaching the ventricular myocardium.

explain the 10 steps of conduction of an action potential through the heart

1. SAN fires an action potential

2. signal spreads across the atrial surfaces

3. signal reach atrioventricular node

4. atria begin to contract

5. 100 ms delay at atrioventricular node

6. signal travel along the interventricular septum within atrioventricular bundle, down the bundle branches to the purkinje fibres

7. and on the moderator band in the right ventricle

8. signal reaches the papillary muscle of right ventricle

9. purkinje fibres distribute signal to ventricular myocardium, where it spreads through muscle cells

10. atrial contraction ends, ventricular contraction begins

Gap junctions

Structures found near desmosomes in intercalated disks that form channels connecting adjacent heart muscle cells, allowing ions and small molecules to pass directly between cells.

Conduction Via gap junctions

The mechanism by which action potentials spread through the heart muscle cells via gap junctions, facilitating excitation-contraction coupling.

Conduction delay at Atrioventricular node

The intentional delay at the atrioventricular node, where a slow action potential triggers a fast action potential in the internodal tract, allowing time for atrial contraction to complete before ventricular contraction begins.