AQA Biopsychology Practice Exam 2025 – Your All-in-One Guide to Exam Success!

The myelin sheath plays a crucial role in facilitating efficient neural conduction. It is a fatty layer that encases the axons of many neurons, providing insulation. This insulation reduces the loss of electrical charge as the action potential travels along the axon, allowing the electrical impulses to move more rapidly and efficiently from one node of Ranvier to the next.

This saltatory conduction, which occurs at the nodes where the myelin sheath is absent, enables the impulses to leapfrog along the axon, significantly increasing the speed of neural transmission. As a result, neurons can communicate more quickly, which is essential for proper functioning in the nervous system, particularly in processes that require fast reflexes or rapid signal processing. Thus, the correct choice emphasizes the insulating properties of the myelin sheath and its contribution to increasing the speed of neural impulses.