Final answer:
Rods are photoreceptors that operate in low light and provide grayscale vision, cones work in bright light and enable color vision, and ipRGCs are involved in regulating circadian rhythms and the pupillary reflex.
Step-by-step explanation:
Rods, cones, and ipRGCs are types of photoreceptors in the retina that play critical roles in our visual perception.
Rods
Rods are photoreceptors that respond in low light and are responsible for our night vision. They can detect only shades of gray and are more sensitive than cones by a factor of about 1000. Rods contribute to our peripheral vision and motion detection but do not yield color information. The human retina contains approximately 120 million rods.
Cones
Cones, on the other hand, respond in intense light and are responsible for color vision. There are three types of cones, each sensitive to a different primary color (red, green, and blue) to perceive a wide spectrum of colors. Cones are concentrated in the fovea, the central part of the retina, and allow for detailed and colored vision.
ipRGCs
While not mentioned in the question, intrinsically photosensitive Retinal Ganglion Cells (ipRGCs) are another type of photoreceptor in the retina. These cells are not primarily responsible for image-forming but are important for regulating circadian rhythms and the pupillary reflex.