Lesson 6: Electrical properties
Action Potentials
- Membrane contains voltage gated channels
- They all respond to depolarisation
- Influx of sodium ions
- When the channels are open, they are fast to close
- Action potentials are of a fixed amplitude
- Potassium ion channels are slower to open compared to sodium
- Potassium ions channels bring the potential back to resting rate
Different excitable tissues have different Aps
- Retinal ganglion cell - 100mv
- Cardiac monocyte - 100mv
- Pancreatic beta cell - 60mv
Speed of action potential
- Higher temperature the faster
- Larger size the faster
- More myelination the faster
- Disease eg, MS slows down transmission
Myelination
- Nodes of ranvier increase conduction
- Saltatory conduction
Action Potentials
- Membrane contains voltage gated channels
- They all respond to depolarisation
- Influx of sodium ions
- When the channels are open, they are fast to close
- Action potentials are of a fixed amplitude
- Potassium ion channels are slower to open compared to sodium
- Potassium ions channels bring the potential back to resting rate
Different excitable tissues have different Aps
- Retinal ganglion cell - 100mv
- Cardiac monocyte - 100mv
- Pancreatic beta cell - 60mv
Speed of action potential
- Higher temperature the faster
- Larger size the faster
- More myelination the faster
- Disease eg, MS slows down transmission
Myelination
- Nodes of ranvier increase conduction
- Saltatory conduction
