5.1.3: Neuronal Communication Flashcards
What is meant by unidirectional in neuronal communication?
The impulse can only travel in one direction across the synapse.
Why can the impulse only travel in one direction across the synapse?
The neurotransmitter is only released from the pre-synaptic neurone and only diffuses to the post-synaptic neurone.
What is summation in the context of neuronal communication?
The rapid build-up of neurotransmitters in the synapse to help generate an action potential.
What are the two methods of summation?
- Spatial summation
- Temporal summation
What is spatial summation?
Many different neurones collectively trigger a new action potential by combining neurotransmitters to exceed the threshold value.
What is temporal summation?
One neurone releases neurotransmitters repeatedly over a short period of time to exceed the threshold value.
What is the role of inhibitory synapses?
An inhibitory synapse causes chloride ions to move into the postsynaptic neurone and potassium ions to move out.
What effect does an inhibitory synapse have on membrane potential?
It decreases the membrane potential to -80mV (hyperpolarisation), making an action potential highly unlikely.
Fill in the blank: Summation is needed because some action potentials do not result in sufficient concentrations of neurotransmitters being released to generate a _______.
new action potential.
