Anatomically, any structure or organ in a living organism that is sensitive to light and get stimulated by light is called photo receptors. In vertebrates, the neurons present in the retina of eyes called the rods and cones is regarded as a photoreceptor which gets stimulated by light. These neurons are linked to the brain with optic nerve. The membranes present in these parts is regarded the end organ that helps in responding to light falling on the surface by converting to images that can be interpreted by the brain.