Question

what is$\textbf{ Human eye }$ ?

Describe its various parts.

Give its diagram too.

Write about its parts and its working also.

Answer 1

$\textbf{The Human Eye }$:

Human eye is the most important organ. It is used to see the beautiful nature and the natural phenomena. The human eye works on the refraction of light through a natural convex lens made of transparent living material and enable us to see things around us.

$\textbf{The main parts of human eye are }$:

Cornea, Iris, Pupil, Ciliary muscles, eye lens, retina and optic nerves.

1. $\textbf{Cornea}$:

It is transparent part of eye and allow the light to enter in the eyes, it is the outermost part of the eye.

2. $\textbf{Iris}$:

It is a circular diaphragm having a hole in it's centre. This hole is called $\textbf{pupil}$. The circular diapragm has muscles and coloured pigments. The colour of an eye depends on the colour of these pigments. The function of iris is to control the amount of light entering the eye through the pupil. The pupil becomes small when bright light falls on the eye but it becomes wide when there is dim light.

3. $\textbf{Eye lens }$:

The eye lens is a crystalline double convex lens and made of transparent and flexible tissues. It is behind the pupil and help them by the muscles called ciliary muscles. It focuses the images of objects on the retina of the eye.

4.$\textbf{Ciliary Muscles }$:

These muscles hold the eye lens in position. It controls the focal length of eye lens. When these muscles contracts the focal length of the lens increases when they expands they exerts pressure on the lens and decreases focal length.

5. $\textbf{Retina}$:

It acts as a screen to obtain the image of object. It contains number of cells in the form of rods and cones which are sensitive towards light. These cells convert light energy to into nerve impulses or signals.

6. $\textbf{ Optic Nerves }$:

Optic nerve is found by the nerve fibres coming from the retina. It transfers nerve impulses to the brain.

$\textbf{Working of the eye }$:

When will look towards an object light from the object enters the pupil of the eye and falls on the eyelens. The lens forms a real and inverted image on the retina of the eye. The retina of the eye contains special cells in the shape of rods and cones. These cells convert light energy into electrical signals. These electrical signals carried to the brain through the optic nerves.