2. NNeurons have a resting membrane potential of -70 mv AAs ions are moved across the neurons membrane (sodium and potassium) the membrane potential changes TThis movement of ions allows for the transfer of the electrical signal which is the nerve impulse

3. 22 Phases are involved in the generation of a nerve impulse DDepolarization- membrane potential changes from negative to positive due to the movement ions RRepolarization- membrane potential is restored to -70mv so that another action potential can be generated TThe whole process is an “all or none” phenomenon IIt always occurs with the same amount of strength each time

5. AAn initial stimulus causes sodium ion channels to open which leads to depolarization on the membrane PPotential changes from -70 to +30mv OOnce channels are activated and the action potential passes, they are immediately closed off so that they can re-set themselves for the next potential

7. PPotassium ion channels open just as the sodium ion channels close TThis allows repolarization to take place PPotassium flows out of the cell to restore the potential back to -70mv

9. TTime period immediately after the action potential passes by on a neuron TThe cell is unable to generate a new action potential during this time period OOccurs when sodium channels are deactivated, thus enabling them from depolarization TThis period gives potassium time to flow out of the cell and restore the resting potential

11. OOnce the resting potential is restored the cell is ready for the next action potential LLarge axons can conduct up to 1000 impulses per second SSmaller ones can only conduct up to 250 per second

12. TThe action potential is created by the movement of sodium ions into the neuron TThe system is re-set by the flow of potassium ions out of the neuron AAll activity occurs within millisecond OOccurs until the stimulus that started it is stopped, or until you consciously stop it