Generator Potential (AQA A Level Biology)
Revision Note
Written by: Lára Marie McIvor
Reviewed by: Lucy Kirkham
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
The influx of sodium ions establishes an electrical potential difference across the membrane of the axon. This is the generator potential.
Examiner Tips and Tricks
In the following sentence, the words in speech marks are the underlined keywords found in mark schemes - these must be incorporated to achieve the marks:
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.
Use our topic questions to ensure that you are hitting the keywords in your answers!
Last updated:
You've read 0 of your 5 free revision notes this week
Sign up now. It’s free!
Did this page help you?
