Which part is the site of nerve signal transmission and is typically insulated by a myelin sheath?

• A. Dendrites
• B. Axon
• C. Cell body
• D. Myelin sheath

Answer: (B)

Nerve signals are conducted along the axon, the long projection that carries impulses away from the cell body toward synapses. The axon is typically insulated by a myelin sheath, produced by glial cells, which speeds up transmission by allowing action potentials to jump between gaps in the insulation (nodes of Ranvier). Dendrites receive signals and feed them to the cell body, the cell body houses the nucleus and integrates inputs, and the myelin sheath is the insulating layer around axons rather than the site where transmission primarily occurs. So, the axon is the correct choice.