Cones

Cones are one of the two types of photoreceptor cells that are in the retina of the eye which are responsible for color vision. They are also one of the three types of cone-shaped cells in the eye, the others being rods and bipolar cells.

Anatomy

Cones are less sensitive to light than the rod cells in the retina (which support vision at low light levels), but allow the perception of color. They are also able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. Cones are concentrated in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones.

Function

The function of cones is to transform light into a signal that can be used by the nervous system. The cone cells are connected to the visual cortex of the brain via the optic nerve. When light hits the cones, it causes a chemical reaction that sends a signal along the optic nerve to the brain, which interprets the signal as vision.

Types of Cones

There are three types of cones that differ in the wavelengths of light to which they respond. They are called L-cones, M-cones and S-cones for long, medium and short wavelength light. The different responses to light of the three types of cones give rise to our perception of color.

See also

• Rods
• Photoreceptor cell
• Retina
• Color vision
• Fovea centralis
• Optic nerve
• Visual cortex
• L-cones
• M-cones
• S-cones

References

Cones Resources
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