Axones nerviosos - A cross section of a bundle of nerve fibers. Axons (orange) are wrapped in myelin (purple); an extension of the membrane of glial cells. Myelin has high lipid content, and acts to insulate the axons, causing them to transmit nerve impulses much faster.
MICROSCOPIC HAIRS IN INNER EAR: Inner ear help divers (like the one in today's pic) know their up down orientation in water. Sounds under water are magnified. When we hear sounds (whether under water or above) microscopic hairs in our inner ears vibrate.