It provides support, regulates the extracellular concentration of neurotransmitters and provides
The action potential moves along the axon by propagation. When Na gates are open and Na
flows into the cell it becomes depolarize then it spreads to the other sections. However, the
message can only be sent in 1 direction because of refractory period (inactivated loop).
K inside the cell Na outside the cell. 60mV – 80mV.
It maintains a concentration gradient for Na and K transporting 3 Na out and 2 K in.
K have more open channels than Na. So fewer Na diffuse into the cell and more K diffuse
By increasing the cell membrane to be more permeable to K making the cell MORE negative.
By increasing the cell membrane to be more permeable to Na making the cell more positive.
Resting State, Depolarization, Rising phase of Action Potential, Falling phase of Action Potential,
Voltage gates of Na and K are closed, maintain a resting membrane potential (negative inside
positive outside). The Na voltage gates open letting the Na to come into the cell making the cell membrane
potential more positive.
In order for this to happen the depolarization must reach threshold. After a huge spike happen
opening all the Na voltage gates.
Na voltage gates are closed, after a very short delay K voltage gates are open K will rapid move
Action potential have a very small undershoot because it don’t have an inactivation loop that
quickly close off the K pump. Na pump have this so they are faster closing