Photoreceptors are neurons within the light sensitive area of the eye, the retina. There are two main types of photoreceptors: rods and cones. Rods are responsible for light, being sensitive to bright lights; and cones are responsible for color, with their ability to distinguish between different wavelengths. A third type of photoreceptor was discovered in the 1990s, called Photosensitive ganglion cells. These photoreceptors are primarily responsible for the synchronization of an organism's circadian rhythm, and also regulate the release or repression of melatonin, a sleep hormone.
Chat with our AI personalities