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The eye is intricately linked to the brain, with various components working together for vision. Learn about the retina, lens, cornea, and more, and how they contribute to clear vision and light reception. Discover the role of rods and cones, focusing mechanisms, and how the eye adapts for near and distance vision. Explore how the ciliary muscles control lens thickness and how light levels are regulated by the iris for optimal visual health.
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The Eye www.assignmentpoint.com
EYE The eye is an extension of the brain www.assignmentpoint.com
Eye brain proxomity • Can you see : • the optic nerve bundle? • Spinal cord? www.assignmentpoint.com
Cross section You must know the position of: Retina Lens Cornea Sclerotic Optic nerve Cilary muscles Suspensory ligaments www.assignmentpoint.com
Retina – receives the image • Full of light receptors which are sensitive to: • Colour • Light levels • Massive blood supply is also needed Fovea is the main focal point and has greatest density of light receptors www.assignmentpoint.com
Retina receptors • Light receptors are called rods and cone www.assignmentpoint.com
Focusing on objects • The lens and cornea focus the light on the retina www.assignmentpoint.com
Focusing • The lens job is to make the rays hit the same point The red rays will be out of focus www.assignmentpoint.com
Bending light • Light is refracted and bent to focus it as it passes through the lens • Lens thickness can be changed so the amount of bending is changed www.assignmentpoint.com
Near vision • to bend the light more to focus it • Fat lens needed www.assignmentpoint.com
Distance vision • Rays enter the eye closer together • Need less bending • Thinner lens needed www.assignmentpoint.com
Changing lens thickness • Cilary muscles are attached to the lens, when contracted they pull the lens thin • The lens is slightly elastic, its relaxed state is short and fat. www.assignmentpoint.com
Controlling light levels • Your eye are very sensitive and can be damaged by harsh light. • Your iris controls light allowed into the eye by changing the size of the pupil www.assignmentpoint.com