Question

Purkinje fibers arise from
A. Apex of ventricles
B. Middle of ventricles
C. Anterior part of auricles
D. Posterior part of auricles

Answer 1

Hint: The Purkinje fibers are conducting fibers. They are composed of electrically excitable cells. Purkinje fibers are essential for maintaining a consistent heart rhythm. The Purkinje fibers are specific heart muscle tissue which helps in generation of heart impulses.

Complete Answer:
- The Purkinje fibers are located in the inner ventricular walls of the heart. The bundle of His arises from AV nodes and divides into right and left bundle branches located in the interventricular septum.
- The bundle branches give rise to Purkinje fibers. The Purkinje fibers carry the contraction impulse from both the bundle branch to the myocardium of ventricles, during the ventricular contraction part of the cardiac cycle
- The Purkinje fibers help the heart’s conduction system to create synchronized contractions of its ventricles. The electrical origin of atrial Purkinje fibers arrives from the sinoatrial node.
- The electrical impulses are transmitted from AV nodes to fascicular branches via the bundle branches.
- The fascicular branches then lead to Purkinje fibers which provide electrical conduction to the ventricles.
- Purkinje fibers cause the cardiac muscles of ventricles to contract at a paced interval.

So the correct answer is the middle of the ventricles.

Note: In the electrical conduction system of the heart the bundle branches transmits the cardiac action potentials from the bundle of His to the Purkinje fibers. Purkinje fibers transmit signals to all parts of ventricles. The Purkinje fibers are located in a space called subendocardium just beneath the endocardium.