Cone cells
There are three types of cone cells in the eye, each sensitive to a different range of wavelengths:
* Short-wavelength-sensitive (S) cones: These cones are sensitive to wavelengths from 400 to 500 nm, which corresponds to the colors violet, blue, and green.
* Medium-wavelength-sensitive (M) cones: These cones are sensitive to wavelengths from 500 to 600 nm, which corresponds to the colors green, yellow, and orange.
* Long-wavelength-sensitive (L) cones: These cones are sensitive to wavelengths from 600 to 700 nm, which corresponds to the colors orange, red, and purple.
The different types of cone cells are located in the macula, which is a small area in the center of the retina. The macula is responsible for sharp central vision, and it contains a high concentration of cone cells.
Rod cells
The rods are much more sensitive to light than the cones, but they are not able to distinguish colors. The rods are located in the peripheral areas of the retina, which are responsible for peripheral vision.
The eye perceives different wavelengths of light by combining the signals from the different types of cone cells. When light strikes the retina, it is absorbed by the photopigments in the cone cells. The photopigments then undergo a chemical change that triggers an electrical signal. This electrical signal is then transmitted to the brain, where it is interpreted as an image.
The brain interprets the signals from the cone cells based on the wavelength of light that they absorbed. Shorter wavelengths of light are interpreted as blue, while longer wavelengths of light are interpreted as red. The brain also uses the relative activity of the different types of cone cells to determine the color of an object. For example, if the S cones are more active than the M cones, the brain will interpret the color as blue-green.
The eye is a remarkable organ that is able to perceive a wide range of wavelengths of light. This allows us to see the world in all of its colors and to experience the beauty of nature.