WordNet

a slender and greatly elongated substance capable of being spun into yarn (同)fibre
a leatherlike material made by compressing layers of paper or cloth (同)fibre, vulcanized fiber
any of several elongated, threadlike cells (especially a muscle fiber or a nerve fiber) (同)fibre
Bohemian physiologist remembered for his discovery of Purkinje cells and the Purkinje network (1787-1869) (同)Jan Evangelista Purkinje, Johannes Evangelista Purkinje

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/10/31 19:42:06」(JST)

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The Purkinje fibers (/pərˈkɪndʒiː/ pər-KIN-jee) (Purkinje tissue or subendocardial branches) are located in the inner ventricular walls of the heart, just beneath the endocardium in a space called the subendocardium. The Purkinje fibers are specialised conducting fibers larger than cardiomyocytes with fewer myofibrils and a large number of mitochondria that are able to conduct cardiac action potentials more quickly and efficiently than any other cells in the heart.^[1] Purkinje fibers allow the heart's conduction system to create synchronized contractions of its ventricles, and are, therefore, essential for maintaining a consistent heart rhythm.

History

Purkinje fibers are a unique cardiac end-organ. Further histologic examination reveals that these fibers are split in ventricles walls. The electrical origin of atrial Purkinje fibers arrives from the sinoatrial node.

Given no aberrant channels, the Purkinje fibers are distinctly shielded from each other by collagen or the cardiac skeleton.

The Purkinje fibers are further specialized to rapidly conduct impulses (numerous fast voltage-gated sodium channels and mitochondria, fewer myofibrils than the surrounding muscle tissue). Purkinje fibers take up stain differently from the surrounding muscle cells because of relatively fewer myofibrils than other cardiac cells and the presence of glycogen around the nucleus causes Purkinje fibers to appear, on a slide, lighter and larger than their neighbors, arranged along the longitudinal direction (parallel to the cardiac vector) . They are often binucleated cells.

Function

Heart rate is governed by many influences from the autonomic nervous system. The Purkinje fibers do not have any known role in setting heart rate unless the SA node is compromised. They are influenced by electrical discharge from the sinoatrial node.

During the ventricular contraction portion of the cardiac cycle, the Purkinje fibers carry the contraction impulse from both the left and right bundle branch to the myocardium of the ventricles. This causes the muscle tissue of the ventricles to contract and generate force to eject blood out of the heart, either to the pulmonary circulation from the right ventricle or to the systemic circulation from the left ventricle.^[2]

Purkinje fibers also have the ability of firing at a rate of 15-40 beats per minute if upstream conduction or pacemaking ability is compromised. In contrast, the SA node in normal state can fire at 60-100 beats per minute. In short, they generate action potentials, but at a slower rate than sinoatrial node. This capability is normally suppressed. Thus, they serve as the last resort when other pacemakers fail. When a Purkinje fiber does fire, it is called a premature ventricular contraction or PVC, or in other situations can be a ventricular escape. It plays a vital role in the circulatory system.

Etymology

They are named after Jan Evangelista Purkyně who discovered them in 1839.

References

^ "Purkinje fiber." The American Heritage® Medical Dictionary. 2007. Houghton Mifflin Company 23 Oct. 2016 http://medical-dictionary.thefreedictionary.com/Purkinje+fiber
^ Podrid, Philip J.; Kowey, Peter R. (2010). Cardiac Arrhythmia, Mechanism, Diagnosis and Management.

External links

Anatomy photo: Circulatory/heart/purkinje/purkinje1 - Comparative Organology at University of California, Davis - "Mammal heart, purkinje fibers (LM, Medium)"
Anatomy Atlases - Microscopic Anatomy, plate 05.78
MedEd at Loyola Histo/practical/cardio/hp8-21.html
Human Cardiac Muscle, histology slides at UC San Diego
Cardiac Muscle Tissue with Purkinje Fibers, Lonestar College North Harris Biology

UpToDate Contents

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English Journal

Bitopic Sphingosine 1-Phosphate Receptor 3 (S1P3) Antagonist Rescue from Complete Heart Block: Pharmacological and Genetic Evidence for Direct S1P3 Regulation of Mouse Cardiac Conduction.

Sanna MG1, Vincent KP1, Repetto E1, Nguyen N1, Brown SJ1, Abgaryan L1, Riley SW1, Leaf NB1, Cahalan SM1, Kiosses WB1, Kohno Y1, Brown JH1, McCulloch AD1, Rosen H2, Gonzalez-Cabrera PJ2.
Molecular pharmacology.Mol Pharmacol.2016 Jan;89(1):176-86. doi: 10.1124/mol.115.100222. Epub 2015 Oct 22.
The molecular pharmacology of the G protein-coupled receptors for sphingosine 1-phosphate (S1P) provides important insight into established and new therapeutic targets. A new, potent bitopic S1P3 antagonist, SPM-354, with in vivo activity, has been used, together with S1P3-knockin and S1P3-knockout
PMID 26494861

Climbing fibers encode a temporal-difference prediction error during cerebellar learning in mice.

Ohmae S1, Medina JF1.
Nature neuroscience.Nat Neurosci.2015 Dec;18(12):1798-803. doi: 10.1038/nn.4167. Epub 2015 Nov 9.
Climbing fiber inputs to Purkinje cells are thought to be involved in generating the instructive signals that drive cerebellar learning. To investigate how these instructive signals are encoded, we recorded the activity of individual climbing fibers during cerebellum-dependent eyeblink conditioning
PMID 26551541

Calcium-permeable AMPA receptors trigger vesicular glutamate release from Bergmann gliosomes.

Cervetto C1, Frattaroli D2, Venturini A2, Passalacqua M3, Nobile M4, Alloisio S4, Tacchetti C5, Maura G1, Agnati LF6, Marcoli M7.
Neuropharmacology.Neuropharmacology.2015 Dec;99:396-407. doi: 10.1016/j.neuropharm.2015.08.011. Epub 2015 Aug 7.
The Bergmann glia is equipped with Ca(2+)-permeable AMPA receptors for glutamate, indispensable for structural and functional relations between the Bergmann glia and parallel/climbing fibers-Purkinje cell synapses. To better understand roles for the Bergmann AMPA receptors, herein we investigate on
PMID 26260232

Japanese Journal

Morphometric analysis of progressive changes in hereditary cerebellar cortical degenerative disease (abiotrophy) in rabbits caused by abnormal synaptogenesis

Journal of Toxicologic Pathology 28(2), 73-78, 2015
NAID 130005072421

Morphometric analysis of progressive changes in hereditary cerebellar cortical degenerative disease (abiotrophy) in rabbits caused by abnormal synaptogenesis

Journal of Toxicologic Pathology advpub(0), 2015
NAID 130004842621

Multiform Premature Ventricular Contractions and Polymorphic Ventricular Tachycardia Caused by Purkinje Activity with Slow Conduction in Idiopathic Ventricular Fibrillation

Internal Medicine 53(7), 725-728, 2014
NAID 130003392731

Related Pictures

★リンクテーブル★

リンク元	「プルキンエ線維」
関連記事	「Purkinje」

「プルキンエ線維」

Purkinje fibers
	Isolated heart conduction system showing Purkinje fibers
	The QRS complex is the large peak.
Details
Identifiers
Latin	Rami subendocardiales
Dorlands; /Elsevier	f_05/12361434
TA	A12.1.06.008
FMA	76538
	Anatomical terminology [edit on Wikidata]