synaptic transmission AO1

Question 1

what is a synapse?

Answer 1

• neurons do not make direct contact
• there is a very small gap between neurons called a synapse.

Question 2

how many stages are in the synaptic transmission process?

Answer 2

5

Question 3

first stage of the synaptic transmission process
1) an …. …. called an …. …. travels along the …. of the ….. ….. to the …..

Answer 3

• an electrical impulse called an action potential travels along the axon of the transmitting neuron to the dendrites

Question 4

second stage of the synaptic transmission process
2) this triggers the ….-….. of the ….-….. neuron to …. …… from …. …..

Answer 4

• this triggers the nerve-ending of the pre-synaptic neuron to relapse neurotransmittters from synaptic vesicles

Question 5

third stage of the synaptic transmission process
3) these chemicals …. across the …. and bind with … …. on the …. of the …-…. neuron

Answer 5

• these chemicals diffuse across the synapse and bind with receptor sites on the membrane of the post-synaptic neuron

Question 6

fourth stage of the synaptic transmission process
4) this …. the …-…. neuron to …. the ….. …..

Answer 6

• this stimulates the post-synaptic neuron to transmit the electrical impulse

Question 7

fifth stage of the synaptic transmission process
5) ….: some of the …… is ….. back into the …-….. neuron or is broken down by …..

Answer 7

• reuptake: some of the neurotransmitter is reabsorbed back into the pre-synaptic neuron or is broken down by enzymes

Question 8

what can neurotransmitters either be?

Answer 8

• excitatory
• inhibitory

Question 9

….. potentials …. a neuron’s …. charge and make it … likely for a neuron to ….

Answer 9

excitatory potentials increases a neuron’s positive charge and make it more likely for a neuron to fire

Question 10

….. potentials …. a neuron’s …. charge and make it …. likely to fire

Answer 10

inhibitory potentials increases a neuron’s negative charge and make it less likely to fire

Question 11

what does the process of summation decide?

Answer 11

• whether a postsynaptic neuron fires is decided by the process of summation

Question 12

the …. and ….. influences are ….. : if the net effect on the …… neuron is ….. then the ….. neuron is … likely to fire. if the net effect is ….. it is … likely to fire I.e the inside of the ….. neuron momentarily becomes ….. charged. once the …. … is created it travels …. the neuron. therefore, the …. ….. of the …. neuron is only …. if the …. of the ….. and ….. signals at any one time reaches the …..

Answer 12

the excitatory and inhibitory influences are summed: if the net effect on the postsynaptic neuron is inhibitory then the postsynaptic neuron is less likely to fire. if the net effect is excitatory it is more likely to fire i.e the inside of the postsynaptic neuron momentarily becomes positively charged. once the electrical impulse is created it travels down the neuron. therefore, the action potential of the postsynaptic neuron is only triggered if the sum of the excitatory and inhibitory signals at any one time reaches the threshold.