Synaptic Transmission Flashcards
What is a synapse?
A small gap in between each neuron.
How are signals carried across the synapse?
Neurotransmitters
What happens when the impulse reaches the end of a nerve cell?
The impulse reaches the end of the cell which triggers the neurotransmitter to be released.
How is neurotransmitter released from the presynaptic cell?
Vesicles fuse with the end of the cell membrane to release the neurotransmitter outside the cell.
How does the neurotransmitter move across the synapse?
Diffusion
How is the information from the neurotransmitter received by the post synaptic cell?
The neurotransmitter is taken up by a post synaptic receptor site on the next cells dendrite.
What must happen to the chemical message for the next neurone to be able to transmit it?
The signal is converted back to electrical.
State the direction of transmission.
From the axon of the pre synaptic cell to the dendrite of the post synaptic cell.
Neurotransmitters can have an excitatory effect on cells, what does this mean?
Give an example.
They increase the positive charge in a neuron which makes the cell more likely to fire.
Eg: Adrenaline
Neurotransmitters can have an inhibitory effect on cells, what does this mean?
Give an example.
They increase the negative charge on a neuron which makes the cell less likely to fire.
Eg: GABA
What is summation?
The sum of the excitatory and inhibitory effects on a cell.
If summation is positive, what does this mean for the neurons ability to fire?
Positive summation means the neuron is more likely to fire.
If summation is negative, what does this mean for the neurons ability to fire?
The neuron is less likely to fire.
Action potential of the post synaptic neuron is only triggered if…
The sum of the excitatory effect and inhibitory signal reaches the threshold
