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BOVINE EYE DISSECTION INTRO – Spring 10

BOVINE EYE DISSECTION INTRO – Spring 10. Can humans or non-human animals see in the dark?. Light? Waves of electromagnetic energy Photons = discrete particles of energy Travel in space at high speeds (186,000/mi/second!) Measure in length nanometers (billionth of a meter).

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BOVINE EYE DISSECTION INTRO – Spring 10

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  1. BOVINE EYE DISSECTION INTRO – Spring 10

  2. Can humans or non-human animals see in the dark?

  3. Light? • Waves of electromagnetic energy • Photons = discrete particles of energy • Travel in space at high speeds (186,000/mi/second!) • Measure in length nanometers (billionth of a meter) So, we call these wavelenths Visable to humans  380 – 760 nm

  4. Visible Spectrum of Wavelength - Humans *snakes see infrared

  5. 1. Sclera: covering of eye Anatomy of the Eye 2. Cornea: covers iris & pupil focusing begins (80%) 5. 2. 4. 3. Anterior Chamber (aqueous): clear fluid nutrients/shape 6. 3. 4. Iris: muscle, control of light intake, color (melanin) 5. Pupil: hole in iris --dilates/contract based on available light 1. 7. 6. Lens: adjusts the eye’s focus (20%) accomodation 11. 8. 7. Vitreous Humor: gives eyeball shape 9. 8. retina: transduction rods & cones 10. Optic Nerve 10. 9. Fovea: acuity, cones 11. choroid

  6. Anatomy of the Eye Light entering the eye

  7. Normal Vision Problem in lens Cataracts protein clumping together Problem in the macula (fovea) Macular Degeneration: loss of acuity and center vision

  8. Anatomy of the Eye - Retina Retina: Photoreceptors Transduction of light Into electrical chemical Message Instead of NT Binding to receptor… Light cause cascade of Intercellular messages

  9. Ganglion Cell Axons form optic nerve Cell Layers in the Retina …notice anything funky about the set up?

  10. Duplexity Theory • Rods (scotopic) • -responsible for night vision • very sensitive to light (low levels) • found in the periphery of retina • more than cones • Provide monochromatic info • (Achromatic) • - Provides poor acuity • Night blindness • Cones (photopic): • -responsible for day vision (sensitive to • mod-hi light) • - found in fovea • - provides greater acuity • - trichromatic – color vision • - legally blind (day blindness)

  11. Anatomy of the Eye – Blind Spot blind spot

  12. The blind Spot 1 million nerve fibers

  13. IPSI & CONTRALATERAL PATHWAYS Optic Tract 1/2 axons go to right side of the brain 1/2 go to left side of brain Not the same in all animals – depending on location of eyes Ex: Rabbits & Guinea Pigs

  14. How does the signal get to the Visual Cortex? VIA the Retinal Ganglion Cell Axons OPTIC TRACT OPTIC TRACT

  15. Damage to the optic nerve = Glaucoma Glaucoma: problem in the Anterior Chamber  fluid there doesn’t drain correctly which puts pressure on the back of the eye especially the optic nerve

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