Difference Between Bundle of His and Purkinje Fibers

The Difference between Bundle of His and Purkinje Fibres lies in function, structure, and location in the body. The bundle of His and Purkinje fibres are both components of the cardiac conduction system, playing critical roles in the transmission of electrical signals through the heart. Electrical impulses are sent from the AV node to the Purkinje fibres via the bundle of His, which serves as a bridge connecting the atria and ventricles. In this article, we will learn about his and Purkinje fibres’ bundles, function, location, and differences.

Difference between Bundle of His and Purkinje Fibres

The difference between Bundle of His and Purkinje Fibres are stated below:

Features	Bundle of His	Purkinje Fibres
Location	It is located in wall between two ventricles( Inter ventricular septum).	It is located in the interventricular septum and spread throughout the ventricle.
Discovery	It was discovered by Wilhelm His Jr.	It was discovered by Jan Evangelista Purkinje
Composition	It is made up of purkinje cells, slender and transient cells etc	It is composed of specialised larger sized cells.
Branches	Bundle of His is divided into right and left Branches.	It is not branched but a part of the left branch of His Bundle.
Impulse	It receives the impulse from the AV node.	It receives the impulses from the Bundle of His.
Muscle Contraction	It will not initiate muscle contraction	It will initiate the contraction of ventricles and help in pumping oxygenated blood to all parts of the body.
Second function	It does not function directly in heart beat formation.	This acts as the second pacemaker of the heart.
Speed	The speed of impulse transmission is slow	The speed of impulse transmission is very fast.

What is a Bundle of His?

Bundle of His is a specialized muscle fiber discovered by Swiss Cardiologist Wilhelm His Jr in 1893. This muscle is located in between the Atrium and ventricular chambers of the heart and helps in connecting the Auricular and Ventricular chambers of the Heart. It is composed of cells like slender and broad transitional cells, Purkinje-like cells, and pacemaker cells.

Bundle of His will Branch further to form Left and Right Branches. The left branch is further branched into anterior and posterior fascicles composed of small fibers called Purkinje fibres. The Right branch will spread out to the right ventricle and the left branch of His Bundle will transmit the impulse to the left ventricle.

Functions of Bundle of His

It plays an important role in the electrical impulse conduction of the heart. The following are the main functions of Bundle of His

• Conduction of electrical Impulses
• It helps in synchronised function of the right and left ventricles.
• It help in maintaining the sinus rhythm.
• It prevents irregular heartbeat or arrhythmia.
• It helps in maintaining Atrioventricular delay that helps in achieving complete ejection of blood from the ventricle.

What are Purkinje Fibres?

Purkinje fibres are specialised muscle tissue that works as part of the electrical conduction system of the heart. It was discovered by a Czech Anatomist and scientist Jan Evangelista Purkinje in 1893.This tissue plays an important role in ventricular conduction of impulse and facilitates its contraction. It is located in the subendocardium and composed of special cells larger than normal cardiac muscle cells. They possess a lot of mitochondria and glycogen deposits. They are connected by gap junctions while intercalated discs are absent.

Functions of Purkinje Fibre

Purkinje fibres branches from the left of the bundle of His and covers the ventricular chambers of Heart. The electrical impulse generated by the nodal system (SA, AV node) travels through them and helps in rhythmic contraction of the heart.

• Conduction of electrical impulse
• Initiation of Ventricular contraction
• Spread action potential across ventricles
• Synchronising cardiac cycle

Location of Bundle of His & Purkinje fibre

The following details pertain to the location and anatomy of the bundle of His and Purkinje fibre:

• A group of heart muscle cells with specialised training in electrical conduction make up the bundle of His.
• It can be found between the ventricles and the atria.
• The left bundle branch and the right bundle branch make up the bundle of His.
• The impulse is carried to the left ventricle’s Purkinje fibres via the left bundle branch.
• The impulse travels to the right ventricle’s Purkinje fibres via the right bundle branch.
• Modified cardiac muscles called purkinje fibres aid in the quick conduction of impulses to the ventricles.
• They are situated within the heart’s ventricular wall.

Clinical Significance of Bundle of His & Purkinje fibre

The Clinical Significance of Bundle of His & Purkinje fibre are as follows

• Conduction Pathway: The Bundle of His transmits impulses from AV node to ventricles, ensuring coordinated heart contractions.
• Ventricular Contraction: Purkinje fibres coordinate sequential ventricular muscle activation, vital for effective blood pumping.
• Arrhythmia Connection: Bundle/Purkinje issues can cause arrhythmias, highlighting their role in diagnosing and treating heart rhythm disorders.
• ECG Insight: Changes in ECG patterns related to these structures aid diagnosis of conduction abnormalities.
• QRS Complex: Signifies ventricular depolarization, initiated by the Bundle of His and transmitted through Purkinje fibres, resulting in ventricular contraction.
• Therapeutic Impact: Implantable devices target Bundle/Purkinje for interventions like pacemakers, optimising cardiac function in conduction disorders.

Conclusion – Difference between Bundle of His and Purkinje Fibres

The electrical conduction system of heart that includes Bundle of His and Purkinje fibres helps in rhythmic and synchronised function of heart. The contraction of heart helps in efficient pumping and problems with normal pumping can be due to disorders in the nodal or network of conducting system. This results in Heart block and arrhythmias. A comprehensive understanding of this complicated system is necessary in research, diagnosis, and treatment interventions. Electrophysiological analysis of Heart plays a very important role in Cardiology, surgery and various areas of cardiac research.

FAQs – Difference between Bundle of His and Purkinje Fibres

What is Another name for Purkinje Fibres?

Purkinje fibres are also known as purkinje cardiomyocytes. These are the main network of electric conducting system of heart.

What is the Difference between an AV bundle and a Bundle of His?

The bundle of His comprises nerve fibres that starts from the atrioventricular node to the Purkinje fibres.AV bundle is a specialized excitable neuronal tissue that continues as Bundle of His.

Why is it Named as Purkinje Fibres ?

It is named after scientist Jan Evangelista Purkinje. Purkinje fibres will transmit the electric impulse to ventricle that helps in conduction and initiate contraction of ventricle.

What is the Main Function of the Purkinje Fibres?

Creating a rhythmic contraction of heart muscles is the main function of purkinje fibres.The functioning of purkinje fibres can be studied with the help of electrocardiography.

Where are Purkinje Fibres Present?

They are present in the inner walls of ventricles.They are present in the inner walls of ventricles, this region is called subendocardium.It will help in contraction of lower chambers of Heart.

What is Another Name for the Bundle of His?

The Bundle of His is alternatively known as the atrioventricular bundle.

What is the Difference between Purkinje Cells and Purkinje Fibers?

Purkinje cells release GABA, inhibiting nerve conduction by binding to the postsynaptic membrane. These cells, also called Purkinje fibers, are essential for the cardiac conduction.

What is the Main Function of the Bundle of His?

The Bundle of His coordinates heartbeat rhythm by transmitting electrical impulses from the right atrium to both ventricles, ensuring synchronized contractions and efficient blood circulation.