The intrinsic ability of cardiac muscle to generate action potentials (APS) rhythmically is achieved by the normal pace maker the sino atrial node (S. A node). The SA node is part of the special excitatory and conductive system of cardiac muscle. With the help of a diagram, describe this conductive system how the AP spreads throughout the muscle.

Answer 1

Here is a diagram that illustrates the cardiac excitation and conduction system, showing how the action potential spreads throughout the muscle:


_________________
| |
| Sinoatrial |
| Node |
| (SA Node) |
|_______¦________|

↑

|

|

|
↓

(Internodal
pathways in the atria)

↓


______________
| |
| Atrioventricular |
| Node (AV Node) |
|________________|

↑

|

|

______________________
| |
| Bundle of |
| His |
|____________________|

→


___________________
| |
| Bundle |
| Branches (Purkinje |
| Fibers) |
|_________________|

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