There are two types of light-sensitive cells in the human eye:(a) Where are they found?(b) What is each type called?(c) To what is each type of cell sensitive?


There are two types of light-sensitive cells in the human eye:

(a) They are found in the retina.

(b) They are called rods and cones.

(c) The rods (rod-shaped cells) are sensitive to dim light or low light and are responsible for vision in dim light.

The cones (cone-shaped cells) are sensitive to bright or normal light and are responsible for colour vision and colour discrimination.


Explanation

The retina of our eye contains a large number of light-sensitive cells that respond to light. These specialized cells are known as photoreceptors.

There are two different types of photoreceptors present within the retina:

1. Rods - They are most sensitive to light and dark changes, hence function better in low light conditions (twilight vision) and get bleached quickly in bright light. They are not good for color vision. There are about 120 million rods found in the human retina.

2. Cones - They are not as sensitive as rods for light. Therefore, they function better in bright light conditions (daylight vision), and require more photons of light to become activated. It also makes us see colors, along with helps us to differentiate between various colors. That's why we are unable to see color very well in dark places. Thus, they are used for color vision and for detecting fine details. There are about 6 million cones found in the human retina. 

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Updated on: 10-Oct-2022

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