Sensory Information: Vision and the Eye

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Sensory Information Vision and the Eye

• the better to see you with

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Sensory Information

• Sensory receptors modified ends of sensory
  neurons that are activated by specific stimuli
• Taste receptors receive chemical info
• Outer ear receptors receive sound info
• Thermoregulators receive heat info
• Eye receptors receive light info
• See table on p. 438 of text

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Main parts of the vertebrate eye

• Sclera white outer layer, including cornea
• Conjunctiva covers outer surface of sclera
• Iris regulates the pupil
• Retina contains photoreceptors (light receptors)
• Lens focuses light on the retina
• Aqueous humor watery liquid that protects the
  lens of the eye and supplies the cornea with
  nutrients
• http//www.youtube.com/watch?vfurcepFlfZ4

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Choroid
Sclera
Retina
Cornea
Iris
Optic nerve
Pupil
Lens
Aqueous humor
Optic disk (blind spot)
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Light-sensitive cells

• The human retina contains two types of
  photoreceptors rods and cones
• Rods are light-sensitive but dont distinguish
  colors (90 million)
• Cones distinguish colors but are not as sensitive
  (4.5 million)

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Humans and other mammals focus light by changing
the shape of the lens
Front view of lens and ciliary muscle
Lens (rounder)
Choroid
Retina
Ciliary muscle
Suspensory ligaments
Near vision (accommodation)
Lens (flatter)
Distance vision