Question

Explain the mechanism of vision in the human eye.

Answer 1

Hint The eye helps to see things. Mainly it is based upon the potential difference that is created inside the eye. When the light strikes the retina portion, this generates impulses in the rods and cones in the retina of the eye. The photo-pigments present in the rods cells are generally composed of opsins and retina.

Complete answer:
The eye is the organ in the body by which the organism can see things. The light when emitted by various objects gets captured by the eyes and then the light rays make its path towards the inside of the eye. When the light rays strike the eye, it may be in two forms, like it can be in the parallel form or either in diverging form. No matter in which form the light is, it has to be bent or refracted so that the light rays focus on the retina of the eye.

The function of refracting the light inside the eye is done by the cornea. The light rays having the visible wavelength are focused on the retina of the eye with the help of the cornea and lens of the eye.

When the light strikes the retina portion, this generates impulses in the rods and cones in the retina of the eye. The photo-pigments present in the rods cells are generally composed of opsins and retina.

In the same way the in cons cells, the photo-pigments are retinal and three different proteins of opsins, here retinal are attached with opsins. Whenever light rays fall on these cells called rods and cones, the retinal gets detached from the opsins, and hence it results in the change in the structure of opsin.

This change in the structure influences the change in membrane permeability, which causes changes in the potential differences.

A kind of signal generates an action potential. Hence the action potential generated in the ganglion cells gets transmitted through their axons that mean the optic nerve.

This all reaches through the visual cortex area and the neural nerves get analyzed and then the image formation occurs.

Note: In the eyes, the retina acts as a digital camera for an electronic image sensor. It converts different images into electronic signals and sends them to the optic nerve so that eyes can see it properly. Rhodopsin is the visual pigment that is responsible for scotopic vision.