Which fibers distribute the electrical impulse through the ventricles to coordinate contraction?

Which fibers distribute the electrical impulse through the ventricles to coordinate contraction?

• A. SA node
• B. AV node
• C. Bundle of His
• D. Purkinje fibers

Answer: (D)

Coordinated ventricular contraction depends on a fast, uniform spread of electrical activity through the ventricular muscle. After the impulse moves past the AV node, it travels into the bundle branches and then into a specialized network called Purkinje fibers. These fibers are built for rapid conduction and fan out through the subendocardial region to rapidly distribute the impulse to all ventricular myocytes. This quick, widespread delivery ensures the ventricles depolarize and contract nearly simultaneously, typically starting at the apex and moving upward, producing a strong, coordinated squeeze. Disruption of this rapid network would lead to less synchronized contraction and weaker pumping.

Coordinated ventricular contraction depends on a fast, uniform spread of electrical activity through the ventricular muscle. After the impulse moves past the AV node, it travels into the bundle branches and then into a specialized network called Purkinje fibers. These fibers are built for rapid conduction and fan out through the subendocardial region to rapidly distribute the impulse to all ventricular myocytes. This quick, widespread delivery ensures the ventricles depolarize and contract nearly simultaneously, typically starting at the apex and moving upward, producing a strong, coordinated squeeze. Disruption of this rapid network would lead to less synchronized contraction and weaker pumping.