The heart consists of an electrical conduction system that helps contract the heart muscles. The electrical signals generated by the pacemaker travel through different structures in the heart to cause contraction. The electrical system consists of an atrioventricular node, Purkinje fibres, a bundle of His, a sinoatrial node, and three bundle branches. Let us discuss the bundle of His and Purkinje fibres and differentiate between them.
Bundle of His
The bundle of His or His bundle is a heart muscle that takes part in electrical conduction. The bundle transmits electrical impulses created by the atrioventricular node (AV node) to the apex of the fascicular bundles with the help of bundle branches.
The bundle of His is distributed in both right and left bundle fibres of the heart and divides further to form Purkinje fibres. The electrical impulse is finally transmitted to the heart’s ventricles by the Purkinje fibres in about 0.3 to 0.4 seconds.
The bundle of His is named after the Swiss cardiologist Wilhelm His Jr. who discovered it in 1893.
Purkinje Fibres
Purkinje fibres are located in the heart’s ventricular walls, below the endocardium, in a space called the subendocardium. It is made of fibres that are capable of transmitting electrical impulses. They are quick and efficient in conducting the impulses through the heart muscles and are an important structure for maintaining the synchronisation of ventricular contraction and consistent heart rhythm.
It brings about ventricular contraction by conducting from both the right and left bundle branches to the ventricles. As a result of contraction, the blood is forced to eject out of the ventricles to circulation.
Purkinje fibres can also act as alternative pacemakers when the primary pacemaker (the SA node) fails to perform. Though it creates impulses at a lower rate than the SA node, it can save the heart when all the other pacemakers fail.
The Purkinje fibres were named after a Czech anatomist Jan Evangelista Purkyně who discovered it in 1839.
Bundle of His vs Purkinje Fibres
| Bundle of His | Purkinje Fibres |
| Description | |
| The bundle of His is a heart muscle that takes part in electrical conduction in the heart. | Purkinje fibres are branched fibres that carry the electrical impulse to the ventricles. |
| Location | |
| It is branched into both the right and left bundle branches of the heart, and runs through the interventricular septum. | It i s present in the ventricular walls of the heart. |
| Discovered By | |
| Wilhelm His Jr. | Jan Evangelista Purkyně |
| Electrical Impulse Transmission | |
| It receives electrical impulses from the SA node and transmits them to the fascicular bundles. | It receives electrical impulses from the fascicular bundles and transmits them to the ventricles. |
| Function | |
| It helps in transmitting electrical impulse from the SA node to the ventricles. |
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Also Read:
- Human Heart – Anatomy, Functions and Facts about Heart
- Human Circulatory System – Organs, Diagram and Its Functions
- Blood Circulatory System – Everything You Need to Know
Frequently Asked Questions on Difference between Bundle of His and Purkinje Fibres
Where does the impulse reach first, the bundle of His or Purkinje fibres?
The electrical impulse first starts from the SA node and is transmitted to the bundle of His first, followed by Purkinje fibres.
What is the heartbeat range of Purkinje cells when they act as pacemakers?
The Purkinje fibres can generate a heartbeat range of 20-40 beats per minute when the SA nodes fail.
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