It is an optical sensitive sense organ and It acts like a camera which enables us to
capture the colourful picture of the surroundings.
Parts of Human eye & their function
ii) Eyeball- It is approximately spherical in shape with a diameter of about 2.3 cm.
ii) Sclera- The white part of the eye is called the sclera. It is the tough outer covering of the eye.
So, it acts as a protective layer.
iii) Cornea- The front transparent part of the sclera is called Cornea. It is made of a thin
membrane through which light enter. It is a transparent bulgee convex shape.
Function- * It acts a protective layer.
* It helps to enter the light in the eyeball.
iv) Iris- A dark and colourful muscular tissue which present just behind the cornea is called the
iris.
Its shape is flat and ring-like structure.
Function- It is responsible for colour of the eye.
iv) Pupil- A black hole present in the middle of the iris is called pupil of the eye. It appears black
because light falling on it goes into the eye and does not come back. In other words, It appears
black because no light is reflected from it.
Function- It regulates the amount of light entering the eye by adjusting the size of the iris.
iv) Eye lens- It is a convex lens made of soft, transparent and flexible material like a
jelly which is made of protein.
Being flexible, the eye lens can change its shape (become thin or thick) to focus the light on the
retina.
It is held in position by suspensory ligaments. One end of suspensory ligaments is attached to the
eye lens and other end is attached to the ciliary muscles.
Note:- It becomes thinner to focus distant objects and becomes thicker to focus nearby
objects.
Function- It help to focus the light rays onto the retina in order to create clear images of objects
that are positioned at various distances.
v) Suspensory ligaments- It is the series of fibres that connect the ciliary muscles of the eye
with the eye lens and hold the lens in place.
Note:- A ligament is a fibrous connective tissue.
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