Retina. SEM of a section through a human retina, the light-sensitive tissue that lines the inside of the eye. Light entering the eye passes through several layers of cells before reaching the light receptors. From top to bottom are seen: cell bodies of optical ganglion cells (pale red), which form the optic nerve; cell bodies of bipolar neurons and cell bodies of the receptor cells (red); and the rod (white) and cone (yellow) receptors. Rod cells different
Lymphocyte. Coloured scanning electron micrograph (SEM) of a lymphocyte white blood cell. Lymphocytes are involved in the immune system's defence mechanisms, lymph system, and involved in antibody production.