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parts of human eye and its functions

Asked by Mahek Arora(student) , on 1/10/14


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Parts of Human Eye & Their Functions:

The human eye is a ball about 2.5 cm in diameter. It consists of the following parts:

1) Sclerotic: Sclerotic is the outer coating of the eye which is white in colour, that protects the interior of the eye and provides the shape to the eye.

2) Cornea: The front part of sclerotic is transparent to light and is termed as cornea. The light coming from an object enters the eye through cornea.

3) Iris: Iris is just at the back of cornea. This controls the size of the pupil. It acts like a shutter of a photographic camer and allows the regulated amount of light to enter the eye.

4) Eye Lens: Eye lens is a double convex lens with the help of which image is formed at retina by refraction of light.

5) Ciliary Muscles: The eye lens is held by ciliary muscles. Ciliary muscles help the eye lens to change its focal length.

6) Pupil: At the centre of the iris there is a hole through which light falls on the lens, which is called pupil.

7) Aqueous humour : The space between cornea and eye lens is filled with a transparent fluid called aqueous humour.

8) Vitreous Humour: The space between eye lens and retina is filled with a jelly like transparent fluid called vitreous humour.Eye Image

9) Retins : Retina serves the purpose of a screen in the eye, wherethe images of the objects are formed. Retina is at the back of the eye lens. Retins is made of light sensitive cells, which are connected to the optical nerve.

10) Optic Nerve: Optic nerve carries the information to brain.

11) Principal Axis

12) Blind Spot : The region of eye containing the optic nerve is not at all sensitive to light and is called blind spot. If the image of an object is formed in the blind spot, it is not visible.

13) Yellow Spot : The central part of retina lying on the optic axis of eye is most sensitive to light and is called yellow spot.

14) Eye Lids: Eye lids are provided to control the amount of light falling on the eye. They also protect the eye from dust particles etc.

Hope it will be helpful... :)

Posted by Vartika(student)on 26/2/11

More Answers

how do the lutein and corotenoids help eye protection

Posted by G.shashirekha(parent)on 2/1/14

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The given figure shows the structure of the human eye.

The human eye is roughly spherical in shape with diameter of about 2.3 cm. It consists of a convex lens made up of living tissues. Hence, human lenses are living organs contrary to the simple optical lenses.

Thewhite of the eyeis known as thesclera. It is the tough, opaque tissue that protects the outer layer of the eye.Irisis the coloured part of the eye, and thepupilis the black,

The following table lists the main parts of the human eye and their respective functions.

S. No.

Human eye part

Function

1.

Pupil

Opens and closes in order to regulate and control the amount of light

2.

Iris

Controls light level similar to the aperture of a camera

3.

Sclera

Protective outer coat

4.

Cornea

Thin membrane which provides 67% of the eyes focusing power

5.

Crystalline lens

Helps to focus light into the retina

6.

Conjunctiva

Covers the outer surface (visible part) of the eye

7.

Aqueous humour

Provides power to the cornea

8.

Vitreous humour

Provides the eye its form and shape

9.

Retina

Captures the light rays focussed by the lens and sends impulses to the brain via optic nerve

10.

Optic nerve

Transmits electrical signals to the brain

11.

Ciliary muscles

Contracts and extends in order to change the lens shape for focusing.

Posted by Rudraksh Dixit(parent)on 1/10/14

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