This picture shows a peripheral nerve in cross section. You will be lucky to find a section exactly like this, for reasons mentioned in the manual.

Note the connective tissue layers associated with a nerve. The overall outer covering is the epineurium, between the fascicles is the perineurium and around individual nerve fibres is the endoneurium (not easily seen). The labels 'E' and 'P' are self explanatory.

This slide is important!

The structure of myelinated fibres is very well seen with osmium staining. Osmium tetroxide oxidises myelin to a brown-black colour. The section shows only myelin sheaths and of course adipose cells. In this picture, the blue arrow shows adipose cells. the green arrows point to bundles of nerve fibres. You have to be careful in interpreting this.

Under high magnification, observe that the nerve fibres differ in overall diameter and the thickness of myelin sheath.

Also notice the large, solid-looking adipose cells.