The eye
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The document describes the main parts of the eye and their functions. The retina detects light and sends signals along the optic nerve to the brain. The cornea and lens focus light onto the retina, while the iris controls the size of the pupil to regulate the amount of light entering. The vitreous humor and sclera help give the eye its shape.
The eye
- 1. THE EYE Parts and functions of the eye: Retina- The retina is the light-sensitive inner lining of the back of the eye. Imagine that the eye is like a camera, and the retina is the film. Rays of light enter the eye and are focused on the retina by the cornea and lens. The retina produces an image which is sent along the optic nerve for the brain to interpret, rather like developing a camera film. Sclera- The sclera is the white of the eye and forms the outer coating of the eyeball. Pupil- The pupil is the dark circular hole in the centre of the iris. Lens- The lens is a transparent body behind the iris, the colored part of the eye. The lens bends light rays so that they form a clear image at the back of the eye – on the retina. As the lens is elastic, it can change shape, getting fatter to focus close objects and thinner for distant objects. Iris- The iris is the colored circle surrounding the pupil. It changes the size of the pupil and allows different amounts of light to enter the eye. Optic nerve- The bundle of over one million axons from ganglion cells that carry visual signals from the eye to the brain Vitreous humor- The vitreous is the clear, jelly-like substance that fills the inside of the eye from the lens to the retina. Cornea- The cornea is the transparent membrane which forms the outer coating at the front of the eyeball and covers the iris and pupil. It also focuses light on the retina.