Observations on the Rod and Cone Layer of the Human Retina. a Light and Electron Microscopic Study.

Electron microscopy combined with certain histochemical studies on thin sections of the human retina has provided additional information concerning the mucinous material that occupies the intercellular space between the outer limiting membrane and the retinal pigment epithelium. The myoid region of the inner segments of hotli rods and cones contains an abundance of organelles associated with the intmcellular elaboration of mucinous and proteinaceous substances. It is suggested that this part of the photoreceptor cells is the most likely source of the mucoid ground substance in which the inner and outer segments of the visual cells are suspended. The organelles that are so concentrated in the apical region of the photoreceptor cells are probably also involved in the production of intracellular materials required for photoreception and/or generation and transmission of nerve impulses.