Able to create its own AP (NV isn't required but can change rhythm)
Creates its own AP (travels .8-1 m/sec) to initiate muscle contraction, a muscle that lies in the wall of the right atrium. Sets the basic heart rate at 70-80 impulses per minute. Heart pacemaker. Spreads through myocardium, signaling atria to contract.
AP comes from internodal pathway. Located in the inferior part of the interatrial septum where AP is slowed to .03-.05 m/sec. Insures the two atria contract before two ventricles.
Bundle of His (modified bundle of myocytes). AP quickly come here, entering the interventricular septum.
While in the interventricular septum it divides into the right and left.
The impulse then becomes Purkinje Fibers which approach the apex and turn superiorly into the ventricular walls.
Slow heart rate and arise as branches of the vagus nerve in the neck and thorax. Innervates at the SA & AV nodes and coronary arteries.
Increase rate and force of heart contractions. Travel to heart from cervical and upper thoracic chain ganglia. Innervates at the SA & AV nodes, coronary arteries and cardiac musculature throughout the heart.