Rod cell

Rod cells are photoreceptor cells in the retina that function in less intense light. Rods are named for their cylindrical shape. They are concentrated at the outer edges of the retina (see peripheral vision). There are about 120 million rod cells in the human retina.

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Rods require less light to function than cone cells, and therefore are the primary source of visual information at night. A rod cell can respond to a single photon of light. Cone cells, on the other hand, require tens to hundreds of photons to become activated. Additionally, multiple rod cells converge on a single interneuron, amplifying the signal. This convergence is at a cost to visual acuity, however, since the pooled information from multiple cells is less distinct than if the visual system received information from each rod cell individually.

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The convergence of rod cells also tends to make peripheral vision very sensitive to movement.

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Experiments by George Wald and others showed that rods are more sensitive to the blue area of the spectrum, and are completely insensitive to wavelengths above about 640 nm (red). Thus, rods have little, if any, role in color vision.

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Photoreceptor cell: __NOTOC__Photoreceptor cells are contained in the retina and are responsible for transducing, or converting, light into signals that can be ultimately transmitted to the brain via the optic nerve. In vertebrates there are two types of photoreceptor cells called rods and cones. The human retina con...

Retina: The retina is a thin layer of cells at the back of the eyeball of vertebrates and some cephalopods; it is the part of the eye which converts light into nervous signals....

Peripheral vision: Peripheral vision is that part of vision that occurs at the edges of the field of view....

Rod cell related Images and Photos (experimental)

Cell, The (DVD)	Cell 2, The (DVD)	Cell 2, The (Blu-ray)	Rod Smith
Rod Carew	Rod Carew	Rod Taylor	Rod McKuen
Rod Taylor	Hot Rod (1950)(DVD, Remastered)	The Cell	Rod Cameron