Sensing the Environment

Annotations:

• mechanical energy (toughness, pressure)

1. statocysts
2. lateral line in fish
   1. stereocilia

      Annotations:

      • sensory transducers that protrude from sensory hair cells, shorter
   2. kinocilium

      Annotations:

      • longest, if bends a way the channels will open, starts wiht potassium instead of calcium
3. animal inner ears, cochlea
   1. semicircular canals filled with lymph

      Annotations:

      • rich in K+
   2. ampucilla is cupula with hairs
   3. 20-20,000 Hz human hearing

Annotations:

• specific chemicals interact

Annotations:

• hot or cold

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• light

1. Visual Receptors
   1. blind spot at optic nerve

      Annotations:

      • where blood vessels come in
   2. fovea

      Annotations:

      • greatest concentration of cones are
   3. cone structure

      Annotations:

      • activated by light
      1. rhodopsin

         Annotations:

         • protein in wall of disk
         1. retinal protein gate inside
            1. cis is inactive
         2. transducin: g protein

            Annotations:

            • active after light strikes, from GDP to GTP
         3. phosphodiesterase
            1. alpha binds to GTP

               Annotations:

               • alpha inhibits the PDE
      2. "031 How Rods and Cones Respond to Light"
      3. cGMP gated Na+ channels

         Annotations:

         • in dark, Na+ goes in rod. depolarization, potential decreases when gates close
         1. in light release of transmitter goes down

Annotations:

• electric fields (eels)

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• magnetic fields

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• detect info of internal body fluids for homeostasis, [blood vessels, gut]

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• body movement and position, [muscles, tendons, joints]

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• external stimuli [eyes, etc]