Supporting cells of the nervous system

[scilearner]

Hello everyone,

 

I have a quick question. Ok the endoneurium is a layer of delicate connective tissue that encloses the myelin sheath of a nerve fiber within a fasciculus. Now my question is supporting cells of the nervous system like glial cells usually connect two nerve fibres together, so do they lie outside the endoneurium? Thanks

[TheEtherealChemist]

As a subsidiary to this question (if you don't mind me piggybacking) can somebody explain which cells are myelinated, and why those that aren't myelinated aren't myelinated?