Which network is responsible for transmitting impulses rapidly through the ventricles via gap junctions to coordinate contraction?

Which network is responsible for transmitting impulses rapidly through the ventricles via gap junctions to coordinate contraction?

• A. Purkinje fibers
• B. SA node
• C. AV node
• D. Cardiac fibrous skeleton

Answer: (A)

In ventricular conduction, impulses must spread quickly to make the ventricles contract in a coordinated way, and that rapid spread is provided by the Purkinje fibers. These are specialized conducting cells that form a network inside the walls of the ventricles and extend the impulse from the His-Purkinje system into the ventricular myocardium. They have many gap junctions, which allow ions to flow directly between cells, dramatically increasing conduction velocity and ensuring near-simultaneous depolarization of the ventricular muscle. Think of the overall pathway: the impulse starts in the SA node, travels through atrial tissue, is briefly slowed by the AV node to allow filling, then moves down the bundle of His into the Purkinje network, which rapidly disseminates the signal to the ventricles to produce synchronized contraction. The other structures have different roles: the SA node sets pace in the atria, the AV node creates a delay, and the fibrous skeleton provides insulation and structural support, not rapid ventricular conduction.

In ventricular conduction, impulses must spread quickly to make the ventricles contract in a coordinated way, and that rapid spread is provided by the Purkinje fibers. These are specialized conducting cells that form a network inside the walls of the ventricles and extend the impulse from the His-Purkinje system into the ventricular myocardium. They have many gap junctions, which allow ions to flow directly between cells, dramatically increasing conduction velocity and ensuring near-simultaneous depolarization of the ventricular muscle.

Think of the overall pathway: the impulse starts in the SA node, travels through atrial tissue, is briefly slowed by the AV node to allow filling, then moves down the bundle of His into the Purkinje network, which rapidly disseminates the signal to the ventricles to produce synchronized contraction. The other structures have different roles: the SA node sets pace in the atria, the AV node creates a delay, and the fibrous skeleton provides insulation and structural support, not rapid ventricular conduction.