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.
Inner ear hair cells, Scanning Electron Microscope. Coloured scanning electron micrograph (SEM) of sensory hair cells from the inner ear. These cells are surrounded by a fluid called endolymph. As sound enters the ear it causes waves to form in the endolymph, which in turn cause the hairs to move. The movement is converted to an electrical signal that is passed on to the brain. Each crescent-shaped arrangement of hairs lies atop a single cell.
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.
Electron micrograph of a cross-section of muscle tissue. It is surrounded by the extracellular tissue that acts as the connective tissue. Each muscle fiber is joined together by the connective tissue to make up the complete muscle. Image by Martin Oeggerli