Eyes and Vision

• Looking at Cajal’s diagram of the retinal cells in an eye alongside the diagram above, I believe that component “a” of the sketch represents the pigmented epithelium. Furthermore, I believe cell type “b” is representative of rods while cell type “c” is indicative of the wider cone. Although I do not know what type “d” or “f” are, structure “e” appears to be the nucleus of the cone. Referring to the diagram on the right once more, “g” appears to be a horizontal nerve cell while “h” seemingly represents a bipolar cell and “i” a ganglion cell. Recalling the reading from “Nerve Cells, Neural Circuitry, and Behavior” by Eric R. Kandel, Ben A. Barres, and A. J. Hudspeth, I would guess the “j” is in some way representative of a mass of neural connections and processes connecting the aforementioned ganglion cells to the optic nerve “m.”
• Wikipedia describes a photoreceptor as a “neuroepithelial cell” as the various rods and cones that make up our eyes and the eyes of many other organisms communicate light and color to the brain. Photoreceptors are often on the surface of a retina as they represent the inception of the conversion from light into electrochemical signals.
• As often is the case in biology, the form of photoreceptors meets its function as rhodopsin, a pigment that absorbs  light is stacked much like the thylakoid grana found in the chloroplasts of plant cells. Although most prevalent in rods, rhodopsin works in both of the aforementioned photoreceptors as specific proteins are able to absorb certain wavelengths of light, giving, for instance, the red coloration to a wild-type fly’s compound eye.

Sources: Rhodopsin, the eye and vision powerpoint; https://en.wikipedia.org/wiki/Photoreceptor_cell; “Nerve Cells, Neural Circuitry, and Behavior” by Eric R. Kandel, Ben A. Barres, and A. J. Hudspeth