THE NERVOUS SYSTEM

Here you are the videos we have seen in class about the nervous system and the brain.

THE SENSE OF SIGHT

    The parts of the eye

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  The eye is made up of three layers: the sclera, the choroid and the retina.

Other parts of the eye are: the cornea, lens, pupil, iris, vitreous humour and optic nerve.

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Our eyes are very delicate organs, so we have various features which help protect them:

               – Eyebrows stop sweat from going into our eyes.

               – Eyelids and eyelashes protect our eyes from the air, excess light and foreign bodies.

               –  Lachrymal glands produce tears that keep the surface of the eye moist.

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     Sight is when our eyes receive images and our brains interpret them. Light is essential in this process.

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To be able to see an image, such as a tree in a landscape, light has to enter the eye through the cornea. It then crosses the pupil and the lens, and it reaches the retina, the part of the eye that is sensitive to light.

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The image we are looking at is then projected onto the retina and transformed into a nerve signal. 

 This signal reaches the brain for interpretation through the optic nerve.

texto e imagen propiedad de la editorial vicens vives.