Monday, 10 December 2012

Sense of Sight

The structure of eyes   

Structure of eyes
Suspensory ligament
- holds the lens in its position
Ciliary muscles (ciliary body)
- change the thickness of the lens
- controls the amount of light entering the eye
- the central opening formed by the iris
allows light rays to enter the eye
- helps to focus light rays onto the retina
Aqueous humour
- a transparent liquid which fills the space between the 
   lens and the cornea
- maintains the shape of the eye and helps to refract 
   light rays
- bends and focuses light rays onto the retina
Blind spot
- the region of the retina that lacks receptors
- the part of the retina that is not sensitive to light
- contains a lot of blood vessels and black pigments 
- blood vessels provide nutrients and oxygen to the eye 
- the black pigments absorb light and prevent reflection 
   of light in the eye
Optic nerve
- connects the retina to the brain
- sends impulses from the retina to the brain for 
Fovea (yellow spot)
- the part of retina that is most sensitive towards light
- formed by millions of light-sensitive cells 
- responds to light rays
- enables image formation 
- sends impulses to the brain using the optic nerve
- protects and maintains the shape of the eye
Vitreous humour
- a transparent jelly-like substance which fills the 
   space  between the lens and the retina
- maintains the shape of the eye and helps to refract 
   light rays                

Reason of blinking:

Video with task: How to take care our eyes 
After watching the video, discuss with your friend and list out 5 ways on how to take care our eyes.


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