PHYSIOLOGY
CARDIOVASCULAR PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The fibers lie in the epicardium.
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The fiber has lower density of myofibrils.
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It does not contain intercalated disk.
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It is similar with cardiac muscle.
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Detailed explanation-1: -The Purkinje fibers are specialized conducting fibers composed of electrically excitable cells. They are larger than cardiomyocytes with fewer myofibrils and many mitochondria. They conduct cardiac action potentials more quickly and efficiently than any of the other cells in the heart’s electrical conduction system.
Detailed explanation-2: -The purkinje fibres are found in the sub-endocardium. They are larger than cardiac muscle cells, but have fewer myofibrils, lots of glycogen and mitochondria, and no T-tubules.
Detailed explanation-3: -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 bundle branches to the myocardium of the ventricles.