AQA A Level Biology

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6.1.8 Generator Potential

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Establishment of a Generator Potential

  • When Pacinian corpuscles are stimulated by pressure on the skin this leads to the establishment of a generator potential
    • This happens due to the movement of charged ions across the membrane

  • There is usually an excess of positively charged sodium ions (Na+) surrounding the axon
  • When pressure is exerted on the Pacinian corpuscle the layers of membrane become distorted and the stretch-mediated sodium protein channels in the axon membrane open
    • These channels are referred to as stretch-mediated sodium channels

  • Sodium ions enter the axon via facilitated diffusion
  • This influx of ions changes the electrical potential difference across the membrane
    • This leads to depolarisation
    • This establishes a generator potential

  • The generator potential triggers impulses (action potentials) that travel along the sensory neurone to the central nervous system

Generator potential 1, downloadable AS & A Level Biology revision notesGenerator potential 2, downloadable AS & A Level Biology revision notes

The influx of sodium ions establishes an electrical potential difference across the membrane of the axon. This is the generator potential.

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Pressure causes the "stretch-mediated" sodium ion channels to "deform", causing sodium "ions" to flow into the axon. This causes "depolarisation" which leads to a generator potential.

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