What is the expected outcome when the impulse reaches the Purkinje fibers?

When the impulse reaches the Purkinje fibers, the expected outcome is ventricular contraction. The Purkinje fibers are specialized conducting fibers located in the inner ventricular walls of the heart. Their primary function is to rapidly transmit the electrical impulse from the bundle of His through the ventricular myocardium. This rapid conduction ensures that the ventricular muscle cells contract in a coordinated manner, allowing for an efficient and effective pumping action of the heart.

Once the impulse reaches the Purkinje fibers, it spreads throughout the ventricles, leading to a simultaneous contraction of the ventricular muscle. This contraction is crucial for propelling blood out of the heart and into the aorta and pulmonary artery, thereby maintaining circulation.

In contrast, options like ventricular filling and atrial contraction occur at different phases of the cardiac cycle and are not directly associated with the function of the Purkinje fibers. Additionally, while various factors can influence heart rate, the activation of the Purkinje fibers is specifically related to the pumping action of the ventricles rather than a decrease in heart rate. Thus, the correct outcome associated with the impulse reaching the Purkinje fibers is indeed ventricular contraction.