electrical

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 neurotran
smitter 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)