Light Transduction + Receptive Field

12 Questions | Total Attempts: 69

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Light Quizzes & Trivia

P. 159-162


Questions and Answers
  • 1. 
    What makes photoreceptors unique?
    • A. 

      Only have membrane potential changes

    • B. 

      Hyperpolarize when excited

    • C. 

      Decrease NT release when excited

    • D. 

      2 of the above

    • E. 

      All of the above

  • 2. 
    Rods follow the stimulus change closely, whereas cones have a latency in their response.
    • A. 

      True

    • B. 

      False

  • 3. 
    In the dark, Na channels are closed, preventing Na to enter the OS.
    • A. 

      True

    • B. 

      False

  • 4. 
    In the dark, photoreceptors release NTs continuously
    • A. 

      True

    • B. 

      False

  • 5. 
    As part of the dark current, Na is continuously pumped out of the OS and follows it's concentration gradient and enters the photoreceptor in the IS
    • A. 

      True

    • B. 

      False

  • 6. 
    What is the voltage potential inside a photoreceptor in the dark? What is it in presence of light?
    • A. 

      -60mV; -20mV

    • B. 

      -20mV; -50mV

    • C. 

      -20mV; -60mV

    • D. 

      -50mV; -20mV

  • 7. 
    When a photon of light strikes Rhodopsin, phosphodiesterase (PDE) becomes:
    • A. 

      Active

    • B. 

      Inactive

  • 8. 
    Active PDE results DIRECTLY in conversion of:
    • A. 

      GMP --> cGMP

    • B. 

      Rho -->ospin + all trans retinal

    • C. 

      CGMP --> GMP

    • D. 

      Rho --> active Rho

  • 9. 
    What is the purpose of cGMP in photorecptors?
    • A. 

      Closes Na channels

    • B. 

      Keeps Na channels open

    • C. 

      Inhibits PDE

    • D. 

      Regenerates Rho

  • 10. 
    Light needs to be present during the entire time that Rho is being transformed into opsin and all-trans retinal
    • A. 

      True

    • B. 

      False

  • 11. 
    What is Hartline's definition of a receptive field?
  • 12. 
    The definition of a receptive field is only applied to ganglion cells.
    • A. 

      True

    • B. 

      False

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