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Olfactory bulb

Chemoreceptors. Sensory Transduction. Photoreceptors. Mechanoreceptors. Olfactory bulb. Olfaction. Audition. Vision. Anatomy of the Retina. Direction of light. Pigment layer. Choroid layer. Direction of retinal visual processing. Sclera. Front of retina. Back of retina.

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Olfactory bulb

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  1. Chemoreceptors Sensory Transduction Photoreceptors Mechanoreceptors Olfactory bulb Olfaction Audition Vision

  2. Anatomy of the Retina Direction of light Pigment layer Choroid layer Direction of retinal visual processing Sclera Front of retina Back of retina Fibers of the optic nerve Ganglion cell Amacrine cell Bipolar cell Horizontal cell Cone Rod Photoreceptor cells

  3. Back of retina Cells of pigment layer Phototransduction Cone Rod Outer segment Discs Disc Outer segment Mitochondria Inner segment Inner segment Light absorption Nuclei Retinene Dendrites of bipolar cells Opsin Synaptic terminal Synaptic terminal Enzymes Rhodopsin in the dark: retinene in 11-cis form (inactive) Rhodopsin in the light: retinene changes shape to all-trans form (active) Front of retina Direction of light 11-cis form of retinene all-trans form of retinene

  4. LIGHT (Absorption) DARK Activation of photopigment High concentration of cyclic GMP Activation of transducin (G protein) Activates PDE Cells of pigment layer (Reaction cascade) Cone Rod Takes place in outer segment Takes place in outer segment Na+ channels open in outer segment Decrease in cyclic GMP Discs Closure of Na+ channels in outer segment Outer segment Membrane depolarization (Spreads to synaptic terminal) Membrane hyperpolarization (the receptor potential) Takes place in retina Opens Ca2+ channels in synaptic terminal (Spreads to synaptic terminal) Inner segment Takes place in retina Takes place in synaptic terminal Nuclei Closure of Ca2+ channels in synaptic terminal Takes place in synaptic terminal Release of inhibitory transmitter (inhibition) Release of inhibitory transmitter Synaptic terminal Bipolar dendrites Bipolar cells inhibited (Removal of inhibition) Bipolar cells disinhibited (or, in effect, excited) Graded potential change in bipolar cell Front of retina (If of sufficient magnitude to bring ganglion cell to threshold) No action potential in cell ganglion cell Action potential in ganglion cell No action potential propagation to visual cortex Propagation of AP to visual cortex (occipital lobe) visual perception

  5. Rods versus Cones Properties of Rod and Cone VisionRODS CONES 100 M per retina 3 M per retina Vision in shades of gray Color Vision High Sensitivity Low Sensitivity Low Acuity High Acuity Night vision Day vision Much convergence in retina Little convergence in retina More numerous peripherally Concentrated in fovea What about adaptation?

  6. Color Vision

  7. Anatomy of the Auditory System

  8. The Middle Ear and Cochlea APEX: Wider, more flexible end of basilar membrane (vibrates best with low-freq) BASE: Narrower, stiffer end of BM near oval window (vibrates best with hi-freq)

  9. The Traveling Wave

  10. The Organ of Corti (Stereocilia) Outer hair cells Tectorial membrane Inner hair cells Supporting cell Nerve fibers Basilar membrane

  11. The Hair Cell Potential

  12. SOUND WAVES Tympanic Membrane Vibrates Ossicles Vibrate Oval Window Vibrates Vibration of round window Fluid Movement within Cochlea Energy dissipates (no sound perception) Basilar Membrane Vibrates Takes place in ear Closure of Ca2+ channels in synaptic terminal Hair cell stereocilia bend as the movement of the basilar membrane displaces them in relation to the overlying tectorial membrane in which they are embedded. Graded potential change in bipolar cell Graded potential change in hair cell Action potentials generated in auditory nerve Propagation of AP to auditory cortex (temporal lobe) sound perception

  13. The Transduction Channel

  14. What about Adaptation?

  15. What about the Outer Hair Cells?

  16. What about the Outer Hair Cells?

  17. Cochlear Implants

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