Biological Systems MCAT Practice Exam

What is the function of the Schwann cells and oligodendrocytes in neurons?

1. Control neurotransmitter release

2. Wrap axons in myelin for insulation

3. Produce action potentials

4. Enclose synaptic clefts

The correct answer is: Wrap axons in myelin for insulation

The function of Schwann cells and oligodendrocytes is to wrap axons in myelin, providing essential insulation for the neuronal processes. Myelin serves several key purposes in the nervous system. It facilitates faster signal transmission along the axon by allowing electrical impulses to skip between the gaps in the myelin sheath, known as the nodes of Ranvier, in a process called saltatory conduction. This enhances the speed and efficiency of nerve signal propagation, which is crucial for proper nervous system function. In the peripheral nervous system, Schwann cells are responsible for myelinating individual axons, whereas, in the central nervous system, oligodendrocytes can myelinate multiple axons simultaneously. This difference in function highlights the importance of myelination in both systems, contributing to their ability to support rapid and efficient communication between neurons.