3 - Synaptic Transmission Flashcards
Describe the process of synaptic transmission using all key words
Neurons transmit electrical impulses, known as action potentials between the pre-synaptic neuron and the post-synaptic neuron.
When action potential reaches the pre-synaptic terminal it triggers release of neurotransmitters from vesicles on the pre-synaptic membrane via exocytocis.
The released neurotransmitter diffuses across synaptic cleft (physical gap between the pre-synaptic membrane and post-synaptic membrane) where it binds to specialised receptor sites on the post-synaptic membrane.
Effects terminated by a process called re-uptake. The neurotransmitter is taken back by vesicles in neuron where they are stored for later release. The quicker the neurotransmitter is taken back the shorter the effects.
What are excitatory neurotransmitters?
Causes an electrical charge in the membrane of the post-synaptic neuron resulting in an excitatory post-synaptic potential (EPSP), meaning that the post-synaptic cell is more likely to fire an impulse.
What are inhibitory neurotransmitters?
Cause an inhibitory post-synaptic potential (IPSP), making it less likely that the neuron will fire and impulse.
Define summation
A neuron can receive both EPSPs and IPSPs at the same time. The likelihood that the cell will fire is determined by adding up the excitatory and the inhibitory synaptic input.
The net result of this calculation (summation) determines whether or not the cell will fire an impulse.
How can the strength of an ESPS be increased?
Spatial summation - large number of EPSPs are generated at many different synapses on the same post-synaptic neuron at the same time.
Temporal summation - large number of EPSPs are generated at the same synapse by a series of high-frequency action potentials by a pre-synaptic neuron.
