Are all axons covered with myelin? No; they can be either myelinated or unmyelinated. Myelinated axons are ensheathed along their entire length. The axon caliber (diameter) in mammalian PNS ranges ...

Further unpublished experiments show a similar pearls-on-a-string structure on myelinated axons, Watanabe says. And his team has seen pearling in human axons. Pullarkat points out that there are ...

If you said 'alpha motor neurone' then you'd be right. The nerves that innervate skeletal muscle have fast conducting, large diameter (alpha class) myelinated axons.