BIO SCI N110 Lecture Notes - Lecture 2: Melanin, Sclera, Choroid
12 Jul 2019
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Fri 4. 26. 19 | the eye: structure and function. Clear = want light to go through it. Choroid blood vessels = gets blood through cells of the eye bc cells need oxygen. Melanin = increases resolution, decreases sensitivity: skin pigmentation, also in eye, melanin is dark = absorbs light. Light will be absorbed: good night vision = more melanin. Nourishes cornea = liquid in front of eye, like water. Eye contracts or dilates do this in. Can also happen if you"re excited, nervous, scared evolve as a social signal, focus vision under threat/opportunity. The eye accommodates for close vision by tightening the ciliary muscles, allowing the lens to become more rounded. Distance viewing light rays from distant objects are nearly parallel and don"t need as much refraction to bring them to focus. Clinical problems: refractive errors: changes in the ability of the lens to round up (accommodate) with age. Clinical problems: cataracts clouding of the lens in the eye.
