synaptic transmission Flashcards
What is the synapse?
What happens?
Junction (pre and post synaptic) between two neurons where chemical messages are transmitted
What is a neurotransmitter? What do they stimulate?
Chemical messengers released by neurons.
Stimulating the development of an action potential in other neurons.
In synaptic transmission, what is travelling down the pre-synaptic neuron?
Action potential
What is inside the axon terminal?
What do they contain?
Vesicles, contains neurotransmitter chemicals
What is the gap between the pre and post-synaptic neuron called?
What is the size?
Synaptic cleft, very small
What does the membrane of the post-synaptic neuron have?
Function?
Receptors, detects the presence of of neurotransmitters
What does the membrane of the pre-synaptic neuron have?
Function?
Transport proteins, takes neurotransmitters back into the cell
What is the processs of the synaptic transmission? (5)
- Action potential arrives at the axon terminal
- Vesicles merge to the membrane of the pre-synaptic cell
- Releases neurotransmitters to the synaptic cleft
- Neurotransmitters diffuse across the synaptic cleft
- Reaches post-synaptic cell>SUMMATION
What is summation? (2)
-The combined (summed) effect of all the excitatory and inhibitory neurotransmitter influences on the post-synaptic neuron
-If the threshold is reached, a new action potential will form in the postsynaptic cell
What is the difference between excitatory and inhibitory neurotransmitters?
Excitatory neurotransmitters:
-INCREASE the likelihood of a new action potential forming in the postsynaptic cell.
-When detected by receptors in the postsynaptic cell, these neurotransmitters make electrical charge inside more POSITIVE and MORE likely to fire=DEPOLARISATION
Inhibitory:
DECREASE
NEGATIVE
LESS
HYPERPOLARISATION
Where are the receptors stored?
Where are the neurotransmitters stored?
What does this mean the communication between them is?
Post synaptic
Pre synaptic
Uni-directional
What does uni-directional mean?
What is this due to?
Neurotransmission between neurons can only be passed in one direction.
This is due to the synapse structure e.g. location at the receptors
What happens once the neurotransmitters have been detected by the receptors? (2)
They detach, some are broken down, some are recycled.
Moved back into the pre-synaptic cell in a process called reuptake.
What does reuptake mean?
When does this happen?
-Neurotransmitters are reabsorbed into the presynaptic cell after transmitting a neural impulse.
-Happens at transport proteins and prepares the cell to fire again.
What are SSRIs?
What does it stand for?
-Selective serotonin reuptake inhibitors
-Class of drugs that influence the process of neurotransmission by blocking the transcription of seratonin into the presynaptic cell
