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The following diagram shows cells involved in detecting and responding to itch stimuli - VCE - SSCE Biology - Question 2 - 2015 - Paper 1
Question 2
The following diagram shows cells involved in detecting and responding to itch stimuli. An example of an itch stimulus is the bite of an insect, which can result in ... show full transcript
Worked Solution & Example Answer:The following diagram shows cells involved in detecting and responding to itch stimuli - VCE - SSCE Biology - Question 2 - 2015 - Paper 1
Step 1
Step 2
Describe how a signal is transferred across the synapse.
Answer
The transfer of a signal across a synapse involves several key steps:
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Release of Neurotransmitters: When an action potential reaches the end of a neuron (the presynaptic terminal), it triggers the influx of calcium ions (Ca²+) into the neuron. This influx causes synaptic vesicles filled with neurotransmitters to fuse with the presynaptic membrane and release their contents into the synaptic cleft.
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Binding to Receptors: The neurotransmitters diffuse across the synaptic cleft and bind to specific receptors on the postsynaptic membrane. Depending on the neurotransmitter and receptor type, this binding can result in either excitation or inhibition of the postsynaptic neuron.
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Propagation of the Signal: If the binding is excitatory and the threshold potential of the postsynaptic neuron is reached, a new action potential is generated in the postsynaptic neuron, propagating the signal further along the neural pathway.
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Termination of Signal: Finally, the signal needs to be terminated to prevent continuous stimulation. This can occur by the uptake of neurotransmitters back into the presynaptic neuron, enzymatic degradation in the synaptic cleft, or diffusion away from the synapse.