Question

put the sequence of events in the correct order to describe the initiation and conduction of an action potential through the heart.
instructions
an action potential is delayed at the av node.
an action potential travels up the purkinje fibers.
action potential reaches the av node via gap junctions.
an action potential travels down the bundle branches.
sa node fires an action potential.

Explanation:

The sino - atrial (SA) node is the natural pacemaker of the heart. It initiates the action potential. This action potential then travels to the atrioventricular (AV) node via gap junctions. There is a delay at the AV node to allow the atria to fully contract before the ventricles are activated. After the delay, the action potential travels down the bundle branches and then up the Purkinje fibers, which rapidly conduct the impulse throughout the ventricles for synchronized contraction.

Answer:

1. SA node fires an action potential.
2. Action potential reaches the AV node via gap junctions.
3. An action potential is delayed at the AV node.
4. An action potential travels down the bundle branches.
5. An action potential travels up the Purkinje fibers.