Coloured scanning electron micrograph SEM of a squamous cell on the surface of the skin. This is a flat, keratinised, dead cell. Squamous cells are continuously sloughed off and replaced with new cells from below. Magnification: when prin
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.
frontal-cortex: Scanning electron microscope picture of a nerve ending that has been broken open to reveal the synaptic vesicles beneath the cell membrane. Image by Tina Carvalho. The Cell: An Image Library