- Specialised cells detecting changes in our environment
- Each change in energy levels in the environment is called stimulus.
- The sensory receptors convert the energy into electrical energy (nerve impulse).
Generating nerve impluses
- Channel proteins allow the movement of ions across the membrane. It remains open for ions to diffuse through until concentrations of that ion are equal on both sides of the membrane.
-Neurones have sodium and potassium sepcialised channel proteins. They have a gate that can open/ close the channel.
-Neurone membranes contain carrier proteins that actively transport sodium ions out of cell and potassium ions into cell (also known as the sodium/ potassium pumps. more sodium