What are photoreceptors? Distinguish between the two types.
Photoreceptors are light sensitive receptors in the retina. The two types are rods and cones. Rods are specialized for night vision, while cones are for day-light vision, fine visual acuity, and color. Rods have one type of photopigment, rhodopsin. Cones have photopigments that are short, medium, or long.