Nerve impluses + All or none principle

Threshold

The amount of stimulus.

Repolarization

after Na gates open , K gates reopen to cause K to move out. at the same time Na gates close.the Na/K pump restores the original concentarctions of Na and K , by pumping Na out and K in .

All or none principle

if an axon is stimulated sufficiently ( above the threshold) the axon will trigger an impluse down the lenght of the axon. if not the impluse is not triggered.

At rest (Polarization)

outside of neuron is + charged compared to inside ( Na ions outside , CL and K ions inside). At rest the cell membrane is not permeable to Na ions but very permeable to K ions so they diffuse out of the cells. The Na/K pulls out 3 Na ions outside and 2 K ions inside the cell.

Refractory period

the breif time between the triggering of an impluse along an axon and the axon's readiness for the next impluse.

Action Potential

the change in charge that occurs when gthe gates of the K channels close and the gates of Na channels open , after a wave of depolarization is triggered.

Resting potiental

the difference in charge from the inside to the outside of a cell at rest .

Depolarization

when a neuron is stimulated enough , K ions gates close and gates for Na ions open. Na ions move in while K ions move out. More + charges move in than out , and this neutralizes the - charge inside the cell.