Explain the structure and functioning of Human eye. How are we able to see nearby as well as distant objects?
The human eye has following main parts:
Cornea: Human eye is spherical in shape. It has tough white
coat which protects the interior of the eye. The front portion of this coat is
transparent and is called cornea.
Iris: This is a dark muscular structure behind the cornea.
Unique colour of a person�s eye is because of colour of iris.
Pupil: The small opening in the iris is called pupil. Iris
controls the size of the pupil and thus controls the amount of light entering
the eye. Light enters the eye through pupil.
Lens: Lens is thicker at the middle and is made of transparent
material. Lens focuses the light on the back of the eye; called retina.
Retina: The back of the eye is called retina. It works like a
screen; on which image is formed. There are numerous light-sensitive nerve cells
on retina. These nerve cells are connected to optic nerve.
Formation of Image in Eye: Light rays enter the eye through
pupil and pass through lens. Lens focuses light rays on retina. Real, inverted
and smaller image is formed on retina. Optic nerve carries the message to the
brain. The brain interprets the message and we get the sense of vision.
