Action potential

1. How resting potential is maintained

1.1. Through the sodium-potassium pump

1.2. Through sodium and potassium leak channels

2. How action potential is restored in refractory period

2.1. Polarity changes as action potential travels down axon

2.2. Hyperpolarized membrane in refractory period, cannot fire

2.3. K+ channels, Na+/K+ transporters triggered

2.4. Depolarization occurs

2.5. Resting potential is restored

3. Rapid transmission of an impulse in a myelinated neurone

3.1. Myelin sheath

3.1.1. Some neurons are covered with myelin, made up of schwann cells

3.1.2. Action potential only happens in the small uncovered area in nodes of Ranvier

3.1.3. Action potential will jump from one node to the other -> saltatory conduction

3.2. Diameter of axons

3.2.1. Larger diameter axons have higher conduction velocity

3.2.2. The more ions have space to travel, more likely to travel in the right direction

4. Temporary shift from negative to positive

4.1. Gate M (activation gate)

4.2. Gate H (deactivation gate)

4.3. Gate N

5. Events that occur

5.1. Depolarization - cell becomes less polar

5.2. Repolarization - brings the cell back to resting potential

5.3. Hyperpolarization - cell becomes more negative