Synaptic transmission

Question 1

What is synaptic transmission?

Answer 1

Process by which neighbouring neurons communicate with each other by sending chemical messages across the synapse which separates them

Question 2

What is the synapse?

Answer 2

A gap which separates one neurone from the next one
Presynaptic neurone - neurone as start of synapse
Postsynaptic - neurone receiving end is known as postsynaptic neurone

Question 3

What is the process of synaptic transmission?

Answer 3

Messages transmitted electrically within neurones (electrical impulses) but are transmitted chemically between neurones (neurotransmitters)
When electrical impulse reaches presynaptic terminal it triggers release of neurotransmitters from synaptic vesicles into synapse
Neurotransmitter then taken up by postsynaptic receptor site on the next neurone
Chemical message is then converted back into an electrical impulse and process of electrically transmission continues

Question 4

What are neurotransmitters?

Answer 4

Chemicals which diffuse across the synapse to the next neurone transmitting messages from one neurone to another
Each neurotransmitter has it own specific structures that fits into a post synaptic receptor site which has the specific receptors from that neurotransmitter

Question 5

What is excitation?

Answer 5

When a neurotransmitter increase the positive charge of the postsynaptic neurone
Makes it more likely that an action potential will be triggered
Increasing likelihood that postsynaptic neurone will fire and electrical impulse
Eg. adrenaline

Question 6

What is inhibition?

Answer 6

When neurotransmitter increases the negative charge of the postsynaptic neurone
Makes action potential less likely to be triggered
Decreasing likelihood the postsynaptic neurone will fire an electrical impulse
Eg. seretonin

Question 7

What is summation?

Answer 7

Process of adding up excitatory and inhibitory signals from neurotransmitters to decide if a neurone fires

Question 8

What happens if the net effect is excitatory?

Answer 8

Post synaptic neurone is more likely to fire and action potential
Eg. Glutamate

Question 9

What happens if the net effect is inhibitory?

Answer 9

The postsynaptic neurone is less likely to fire and action potential
Eg. GABA

Question 10

What is needed for a neurone to fire and action potential?

Answer 10

A specific threshold of positive charge must be reached inside the neurone