1. electrical impulses move down the axon • electrical impulses cannot jump the synapse as electricity • they must be converted into chemical signals electrical chemical electrical

2. electric chemical

3. electrical transmission down the axon electrical conversion to chemical at the synapse chemical electrical conversion to electrical at next neuron

4. Synaptic Transmission of Impulse • the players • vesicles • neurotransmitters (NT) • receptors • pre-synaptic membrane • synapse • post-synaptic membrane • the play • electrical signal moves down axon • signal changed to chemical by NT • receptors MIGHT make post-syn neuron “fire” • signal then moves down to next neuron

5. Synaptic Transmission of Impulse 1. electrical impulse moves down to axon terminal

6. Synaptic Transmission of Impulse 2. vesicles begin to move toward synaptic membrane

7. Synaptic Transmission of Impulse 3. vesicle fuses with synaptic membrane neurotransmitter molecules are released into synapse

8. Synaptic Transmission of Impulse 4. neurotransmitters are “caught” by receptors (receptors are on membrane of dendrite of post-synaptic cell)

9. Synaptic Transmission of Impulse • 4 (b) • NTs bounce out of receptors • broken down • recycled • an enzyme breaks down the NT • for NT acetylcholine, enzyme is acetylcholinesterase 4b

10. Synaptic Transmission of Impulse 5. NT reuptake neurotransmitters are reabsorbed this is called “REUPTAKE” (might involve a TRANSPORTER)

11. Synaptic Transmission of Impulse 6. fragments are recycled and rebuilt if no recycling, eventual depletion (but this takes a long time)