Question

Purkinje fiber is found in
(a) Brain
(b) Kidney
(c) Skin
(d) Conductive system of the heart

Answer 1

Hint: Purkinje fibers are specialized cells that function in the conduction of electrical impulses throughout the ventricles of following the impulses from the AV node.

Complete step by step answer:
Purkinje fibers are electrically excitable cells of myocardial tissues which have fewer myofibrils and more mitochondria, they are dedicated to the conduction of the electrical impulses generated in the SA node through the walls of the ventricles. They are connected to the Bundle of his just below the AV nodes. The conduction is such that action potential is reached very easily and more efficiently as compared to other cardiac tissues.

- The cardiac conductive system is a complex system of cardiomyocytes that are excitable in nature and take part in the periodic contraction of all muscles of the heart.
- The impulse is generated from the Sinoatrial node (SA node) and carried by the atrial fibers along the right and left atrium which is then distributed to the Bachmann's bundle. Through the internodal tracts, it travels to the Atrioventricular node which delays the pace of transmission, from here the impulse travels to the Bundle of his which is further divided into a left bundle and right bundle branches. The conduction pathways further progress to the thick- walled ventricles through the Purkinje fibers. Which excites the ventricular musculature causing them to contract.
- As the wave of excitation spreads across the atrial muscle, it contracts and blood gets filled into the ventricle, the AV nodal delay prevents the simultaneous contraction of the atrium and ventricles and gives the ventricles enough time to be filled with blood prior to contraction.
So, the correct answer is ‘(d) Conductive system of heart'.

Note:
The Sinoatrial Node is also called a pacemaker and the Atrioventricular Node is called the Pace- setter of the heart because the SA node generates the electrical impulses and the AV node delays the reaching of impulses to the ventricles.