Neurone at rest

• Sodium ion-potassium ion (Na+/K+) pump actively transports 3 sodium ions out and 2 potassium ions in per ATP molecule hydrolysed
• More positive charge flows out of the neurone than comes in, leading to an overall positive charge outside and negative charge inside
• Resting membrane has higher permeability to potassium ions than sodium ions
• Higher number of potassium ion leak channel proteins and lower number of sodium ion leak channel proteins in the membrane
• Potassium ions can diffuse back out of the neurone easily, while sodium ions find it difficult to diffuse back in
• This enhances the charge difference between the outside (positive) and inside (negative) of the neurone