What is the function of the myelin sheath in neurons?

The myelin sheath is a critical structure in neuronal physiology, serving primarily to insulate axons and significantly increase the speed of electrical impulses, or action potentials, along the neuron. This insulation allows for more efficient transmission of signals, as it reduces the loss of ions and minimizes capacitance along the axon.

In myelinated neurons, action potentials jump between the nodes of Ranvier, which are gaps in the myelin sheath, in a process known as saltatory conduction. This mechanism not only speeds up the transmission of nerve signals but also conserves energy for the neuron, as fewer ions need to be exchanged across the membrane.

The other options, while related to neuronal function, do not accurately describe the role of the myelin sheath. It does not protect the cell body directly, facilitate neurotransmitter release, or store energy for the neuron. Therefore, the primary and established function of the myelin sheath is to insulate axons and enhance the speed of impulse conduction.