Purkinje fiber
Pronunciation: pur-KIN-jee FY-ber
Specialized cardiac conduction cells that rapidly transmit electrical impulses throughout the ventricular myocardium.
Full Definition
Purkinje fibers are highly specialized cardiac myocytes that form the terminal portion of the cardiac conduction system, responsible for rapid and coordinated transmission of electrical impulses throughout the ventricles. These cells are larger than ordinary myocytes, contain fewer myofibrils, and have abundant glycogen, giving them a characteristic pale, clear cytoplasmic appearance on histologic examination. Located primarily in the subendocardial region, Purkinje fibers can extend into the ventricular septum and papillary muscles. Pathological involvement of these fibers can result in ventricular arrhythmias and conduction abnormalities. They are particularly susceptible to certain toxins and can be sites of arrhythmogenic foci.
Usage
Usage note: Always capitalize 'Purkinje' as it is an eponym. Use 'fiber' rather than 'fibre' in North American contexts.
In Context
- "The subendocardial Purkinje fibers showed vacuolar degeneration consistent with drug toxicity." — Forensic autopsy report
- "Normal Purkinje fibers were identified in the left ventricular septum with characteristic pale cytoplasm." — Cardiac pathology assessment