What Are Purkinje Fibers?

A special fiber in the conduction system. It was first described by Purk-ingje in 1845, and was named after him as recognized by subsequent scholars. It is the terminal branch of the left and right bundle branches and their branches, and is interwoven into the net under the endocardium and deep into the ventricular muscle. The subendometrial Purkinje fiber network is most abundant in the middle and lower parts of the septum, apex, and papillary muscle base, but scarce in the upper part of the septum, around the arterial orifice, and at the bottom of the heart. The middle and lower part of the left side of the ventricular septum is distributed into a fine mesh by the left bundle branch group. The upper Purkinje fiber is scarce, the upper anterior part is scarce than the posterior superior part. ^[1]

Purkinje fiber

A special fiber in the conduction system. It was first described by Purk-ingje in 1845, and was named after him as recognized by subsequent scholars. It is the terminal branch of the left and right bundle branches and their branches, and is interwoven into the net under the endocardium and deep into the ventricular muscles. The subendometrial Purkinje fiber network is most abundant in the middle and lower parts of the septum, apex, and papillary muscle base, but scarce in the upper part of the septum, around the arterial orifice, and at the bottom of the heart. The middle and lower part of the left side of the ventricular septum is distributed into a fine mesh by the left bundle branch group. The upper Purkinje fiber is scarce, the upper anterior part is scarce than the posterior superior part. ^[1]

Chinese name

Purkinje fiber

Foreign name

Purkinje's fibre

Form

Purkinje cell

status quo

Fibrous network

Purkinje fiber

Purkinje's fibre

Found in the heart of sheep by JE Purkinje. It is a fibrous network-like structure formed by Purkinje cell chains and connected to the atrioventricular bundle. The excitement of the atrioventricular node is transmitted here through the atrioventricular bundle, and then to the papillary muscle system constituting the intraventricular chamber. It is larger in diameter and more sarcoplasmic than normal myocardium. The number of myofibrils is small. In the peripheral part of the cell, the nucleus is in the center of the cell.

Purkinje fibers, also known as bundle cells, are a special type of myocardial fiber. It is a component of the cardiac conduction system, which forms the atrioventricular bundle and its branches, and is distributed in the subendocardium of the ventricle. Its morphological characteristics are: shorter and wider than ordinary cardiomyocytes, rich in mitochondria and glycogen in the cytoplasm, and less myofibrils, and mostly located around the cells, so its cytoplasmic staining is more common in HE-stained sections Myocardial cells are shallow. There are many connection structures between cells, and pannus are more common. The Purkinje fiber at the end of the branch of the atrioventricular bundle is connected to ordinary ventricular muscle fibers, transmitting impulse to all parts of the ventricle.

Purkinje fiber has a maximum repolarization potential of -90mv, which is a fast-responding cell. In the process of automatic depolarization, it is completed by progressively opening sodium ion at -60mv through the If channel. Unlike the depolarization of sinoatrial node P cells, it is accomplished by the progressive decay of potassium ions through Ik channels.