Question

Which one of the following is the correct difference between rod cells and cone cells of our retina?
A. Rod cells-vision in poor light; cone cells- colour vision and detailed vision in bright light.
B. Rod cells- more concentrated in the centre of retina; cone cells- evenly distributed all over the retina.
C. Rod cells- low in number; cone cells- high in number.
D. Rod cells- rhodopsin; cone cells- rhodopsin.

Answer 1

Hint: Rod cells and cone cells are photoreceptor cells that are present in the retina of our eyes, and have been named on the basis of their physical morphologies.

Complete solution:
The eye is one of the most complex as well as an important sense organ that we humans are endowed with. Because of our pair of eyes, we are able to visualize things around us. It not only helps us in visualizing objects but also helps us in light perception, identifying different colors, and depth perception. The functioning of our eyes is quite similar to that of a camera. Both of them help us in visualizing objects when light (coming from outside) enters into them. Let’s try to understand the structure and function of the human eye in detail. It is a spherical ball having diameter roughly about 2.3cm. It is filled with some fluid. It consists of the following parts:
Sclera is the white, tough outer covering, which is protective in nature. It is the white part of our eye.
Cornea is the transparent part of the sclera which is visible from the front. It is the point from where light enters our eye.
Iris is the dark muscular tissue, ring-like structure present behind the cornea. The color of the iris indicates the color of the eye. It helps in regulating or adjusting exposure by adjusting the iris.
Pupil refers to the small opening in the iris, whose size is controlled by the iris. It functions by controlling the amount of light entering our eye.
Retina is a light-sensitive layer. It consists of numerous nerve cells. It functions by converting images formed by the lens into electrical impulses. These electrical impulses are further transmitted to the brain by making use of optic nerves.
Optic nerves are mainly of two types. These include cones and rods.
Cones: Cones are those nerve cells that are more sensitive to bright light. They help in detecting a wide spectrum of photons of light. These cells are responsible for color vision.
Rods: Rods are the optic nerve cells that are more sensitive to dim lights. They help in peripheral vision.

So, the correct answer is option A.

Note: In order to keep our eyes healthy, we need to include leafy vegetables, whole grains, cereals, citrus fruits like cherries in our diet. We should not wipe it or rub it harshly, since it is a sensitive organ.