Nerve bundle. Coloured scanning electron micrograph (SEM) of a freeze-fractured section through a bundle of myelinated nerve fibres. Myelin sheaths (yellow) can be seen surrounding the axons (blue). Perineurium (connective tissue, pink) surrounds the nerve bundle while endoneurium divides the individual fibres.
That bacteriophage under a SEM that Corpsegoddess shared from Twitter to the O-deck last night was pretty cool. I would never have guessed that they looked so much like their sterile biology textbook diagram brethren.