eye_upper_slim part of part of neuronal receptor cell photoreceptor cell eye photoreceptor cell eye photoreceptor cell Eye photoreceptor cells, also commonly known as photoreceptors, are specialized types of cells found in the retina, the light-sensitive layer at the back of the eye. They are integral to the complex process of vision, as they are directly involved in converting light into electrical signals. This process is known as phototransduction. There are two primary classes of photoreceptor cells; rods, which function mainly in dim light and provide black-and-white vision, and cones, which function in brighter light and allow for the perception of color. Rods and cones carry out their roles through sophisticated biochemical reactions. The main component of these reactions is a protein called opsin, which binds to a small molecule known as retinal. In the presence of light, retinal changes its shape, leading to a series of chemical reactions that result in changes to the cell’s electrical potential, thus creating an electrical signal that travels to the optic nerve. Rod cells possess only one kind of opsin, called rhodopsin, which only allows them to distinguish between light and dark. Conversely, cone cells have three types of opsins, allowing for the differentiation of various colors. The spatial distribution of these cell types throughout the retina also contributes to their function. Rod cells are more numerous and are distributed more at the periphery of the retina, contributing to peripheral and night vision. On the other hand, cone cells are concentrated in the macula, a tiny central region in the retina, and with the highest density in the fovea, a small pit in the macula. This distribution of cones lies at the base of fine detail and color vision in the central visual field. In summary, eye photoreceptor cells carry out the primary function of transforming light into visual signals, a role that is crucial for the overall process of vision. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) Any photoreceptor cell that is part of some eye. ZFA:0009154 https://cellxgene.cziscience.com/cellguide/CL_0000287 Homo sapiens eye