This video from the Khan Academy on You Tube describes the anatomy of the neuron.
The Anatomy of a Neuron
Video Sep 12, 2017
Aerogels are the world's lightest (least dense) solids. They are also excellent thermal insulators and have been used in numerous Mars missions and the Stardust comet particle-return mission. The focus of this video is silica aerogels, though graphene aerogels are now technically the lightest.