What type of axons are wrapped in myelin and conduct signals faster via saltatory conduction?

• A. Unmyelinated axons
• B. Myelinated axons
• C. Demyelinated axons
• D. Motor neurons

Answer: (B)

The speed of neural signaling increases dramatically when axons are wrapped in myelin because myelin acts as an insulation that reduces leakage and lowers the membrane’s capacitance. In myelinated fibers, the action potential only needs to be regenerated at the gaps in the sheath called nodes of Ranvier. The signal effectively hops from node to node, a process known as saltatory conduction, which makes the transmission much faster than if the impulse had to travel every millimeter of membrane.

If axons aren’t myelinated, the depolarization has to occur along the entire length of the membrane (continuous conduction), which is slower. Demyelinated axons lose this insulation and conductance drops, leading to slower or failed signaling. The term motor neurons isn’t about the conduction speed itself; they can be myelinated or not, but the rapid saltatory conduction specifically depends on the presence of myelin.