Download SYNAPTIC TRANSMISSION

SYNAPTIC TRANSMISSION
TODAY’S TASK: Your job, in your groups, is to produce a complete
representation of synaptic transmission using the materials
provided.
You must include the following stages and be able to explain the
entire process to the class. You should label the key features of the
synapse using the coloured paper.
EXTENSION TASK: include a representation of what happens in
schizophrenia.
1. When a nerve impulse travels down an axon it arrives at the
pre-synaptic terminals.
2. This arrival triggers the release of neurotransmitters which
diffuse across the synaptic cleft.
3. When released, the neurotransmitter must be taken up
immediately by the post-synaptic neuron, otherwise it will either be
re-absorbed by the synaptic terminals from which it was released
OR it will be chemically broken down by enzymes in the synaptic
cleft thus making it inactive.
4. If successfully transmitted, the nerve impulse is then carried
along the post-synaptic neuron until it reaches the next synaptic
terminal where the message will continue to pass on via electrical
impulses.
KEY TERMS
Synapse: the gap between the end of one neuron and the dendrites of the next
neuron.
Neurotransmitter: a chemical substance released from a synaptic vesicle that affects
the transfer of an impulse to another nerve or muscle.
Synaptic transmission: Additional Information
 Neurotransmitters include: dopamine, acetylcholine and
serotonin. These can all influence the post-synaptic neuron to
respond in an inhibitory way (decreases the firing of a cell) or
an excitatory way (increases the firing of a cell).
 Schizophrenia, for example, is a mental disorder thought to be
the result of excessive activity of the neurotransmitter
dopamine. This means that neurons which respond to
dopamine fire too often (they are too excitatory) and transfer
too many messages through the brain as a result. When this
happens symptoms of schizophrenia start to occur.
 These symptoms can be controlled with anti-psychotic drugs
e.g. chlorpromazine, which are designed to block the receptor
sites for dopamine.