Final answer:
Purkinje fibers conduct action potentials quickly due to low resistance to ion flow and high capacitance, which facilitate rapid and effective electrical impulse transmission necessary for heart contractions.
Step-by-step explanation:
Purkinje fibers conduct action potentials so quickly due to option A) Low resistance to ion flow; High capacitance. These fibers are specially adapted myocardial conductive fibers that rapidly spread impulses through the myocardium. They feature a large diameter and are rich in gap junctions, which provide low resistance pathways for ions to flow. This anatomical adaptation is analogous to electrical wires with wider diameters that allow for more rapid electrical conductivity. Moreover, their high capacitance allows the action potential to be maintained without a significant decrease in amplitude, ensuring rapid and effective transmission of the electrical impulse throughout the ventricular myocardium.
During the action potential transmission in cardiac conductive cells, including Purkinje fibers, voltage-gated calcium ion channels and sodium ion channels play significant roles by enabling a swift influx of ions that contribute to the rapid depolarization necessary for effective heart contractions.
The speed of conduction is also influenced by the myelination of axons and the diameter of the axon itself, which reduces internal resistance and allows faster transmission. This is similar in concept to Purkinje fibers but tailored to their specific function within cardiac tissue, where efficient impulse propagation ensures that the heart beats in a synchronized manner.