A nerve impulse is propagated across a synapse when the neurotransmitter acetylcholine is released from the pre-synaptic membrane and diffuses across the 20 -nm-wide synaptic cleft to the post-synaptic membrane. a. How long does it take a nerve signal to cross a synapse? You can assume that the synaptic fluid is essentially water. b. What is the speed of transmission, in m/s?
