synaptic transmission

Question 1

Outline snaptic transmission 5 steps?

Answer 1

1) Positive charge (action potential) firing through axon of presynaptic ( neuron ( if charge is + more likely to burst vesicle)

2) Vesicle release neurotransmitter into the synaptic cleft
3) NT received by postsynaptic receptor sites

4) If charge is strong enough / enough of it → summation →the next cell is inhibited or excited ( fires next neuron if has positive charge more likely to fire enough received or doesn’t)
5) Any leftover neurotransmitter in the synaptic cleft is reabsorbed into presynaptic neuron

Question 2

What is the action potential ?

Answer 2

The electric signal that travels down the neuron
* the electrical impulse that travels down the axon

Question 3

What is summation ?

Answer 3

Effects of all inhibitory and excitatory NT influences on the postsynaptic cell.
The net of this calculation determines whether or not cells are fired - if E outweigh I the cell is likely to fire

Question 4

What is exitation?

Answer 4

• receptor stimulation increase in positive charge of postsynaptic neurons
  → increase the likelihood that an excitatory cell is sent to post synaptic cell which is then more likely to fire. ‘ creates a EPSP’

Question 5

What is inhibition?

Answer 5

• receptor stimulation results in negative charge of Postsynaptic neuron
  → they decrease the likelihood of that neuron firing. ‘ creates a IPSP’

Question 6

What is summation?

Answer 6

All these inputs are summed in a process called summation so if the excitation outweighs inhibition then the next cell will fire.

Question 7

What is temporal summation?

Answer 7

• refers to the added effect of EPSPs and IPSPs within an interval

Question 8

what is spatial summation?

Answer 8

the added effect of ESPs and IPSPs at one location

Question 9

Distinguish between excitation and inhibition (2)

Answer 9

Inhibition is where the NT binds with a receptor and makes it less likely the cell will fire, inhibits the response whilst excitation is where it makes it more likely the next cell will fire.

Question 10

Outline the process of synaptic transmission? (6)

Answer 10

Action potential arrives at the end of the presynaptic cell stimulating the vesicles to release neurotransmitters into the synaptic cleft(Exocytosis).Nt diffuses across the synaptic gap towards post synaptic membrane where it binds with receptor sites. When it arrives if its an inhibitory NT it creates an IPSP making it less likely the next action will fire. If its an excitatory NT then it will make an EPSP making it more likely the next action.All these inputs are summed in a process called summation so if the excitation outweighs inhibition then the next cell will fire.

Question 11

Out line the summation aspect

Answer 11

When it arrives if its an inhibitory NT it creates an IPSP making it less likely the next action will fire. If its an excitatory NT then it will make an EPSP making it more likely the next action.All these inputs are summed in a process called summation so if the excitation outweighs inhibition then the next cell will fire.