Bangs It's Gone....
a:  Action potential ~
b:  firing a gun
What:  Page 42 of the linked book. It is an all or nothing phenomena. Once it happens, the impulse doesn't stop until it gets to the synapses. This is somewhat like a bullet not stopping until it hits something.
Useful?
Writer:  Ellen E. Pastorino
LCC: 
Where:
Date:   Apr 30 2013  10:11 AM
# 2791 Critique Analogy
