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Section of the heart showing the Ventricular Septum
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The QRS Complex is the large peak in the diagram at the bottom
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(or Purkyne tissue) are located in the inner
Ventricular walls of the
Heart , just beneath the
Endocardium . These fibers are specialized
Myocardial fibers that conduct an electrical
Stimulus or impulse that enables the heart to contract in a coordinated fashion.
Because of their specializations to rapidly conduct impulses (numerous
Sodium Ion Channel s and
Mitochondria , fewer
Myofibril s than the surrounding muscle tissue), Purkinje fibers take up stain differently than the surrounding muscles cells, and on a slide, they often appear lighter and larger than their neighbors.
Purkinje fibers work with the sinoatrial
Node (
SA Node ) and the atrioventricular node (
AV Node ) to control the
Heart Rate .
During the ventricular contraction portion of the cardiac cycle, the Purkinje fibers carry the contraction impulse from the left and right to the
Myocardium of the ventricles. This causes the muscle tissue of the ventricles to contract and force
Blood out of the heart — either to the
Pulmonary circulation (from the right ventricle) or to the
Systemic circulation (from the left ventricle).
The impulse through the Purkinje fibers is associated with the
QRS Complex .
Purkinje fibers also have the ability of automaticity - they generate action potentials, but at a slower rate than
Sinoatrial Node and other atrial
Ectopic Pacemakers . Thus they serve as the last resort when other pacemakers fail.
They were discovered in
1839 by
Jan Evangelista Purkinje , who gave them his name.
