Purkinje Fibers
Other Known Aliases – subendocardial branches
Definition – specialized conducting fibers composed of electrically excitable cells located just beneath the subendocardium in the inner ventricular walls of the heart
Clinical Significance – these cells actually conduct cardiac action potentials faster and more effeciently than any other cells in the heart and are responsible for the synchronized contractions of the ventricles during depolarization. They also have intrinsic pacemaking ability at 20-40 bpm to act as a back-up pacing system.
History – Named after Jan Evangelista Purkinje (1787-1869), a Czech anatomist and experimental physiologist who received his medical doctorate from Charles University in Prague in 1818. He would be appointed Professor of Physiology in Breslau in 1823 and did revolutionary work on vision. He would later create the world’s first Department of Physiology at the University of Breslau in Prussia in 1839 and the world’s second official physiology lab in 1842. During his career of physiologic discovery and research, he discovered large neurons with branching dendrites in the cerebellum (Purkinje cells), describe the change in brightness of red and blue colors as light intensity decreases (Purkinje shift), and the eye’s reduced sensitivity to dim red light compared to dim blue light (Purkinje effect). He also was the first scientist to present work on the cellular theory of biology, the first to use the term “protoplasm” to describe the fluid in cells, and the first to report on the individuality of fingerprints. But it was in 1839 when he described his eponymous fibers of the heart. He was one of the best known scientists of his era and was so famous, people would address letters to him and simply put “Purkinje, Europe”.
References
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- Cavero I, Guillon JM, Holzgrefe HH. Reminiscing about Jan Evangelista Purkinje: a pioneer of modern experimental physiology. Adv Physiol Educ. 2017; 41(4):528-538. [pubmed]
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