KA4- Impulses Across Synapse

Question 1

1) Neurons connect…/…13 Neurotransmitters relay… 7

Answer 1

with other neurons or muscle fibres/ glands at a synaptic cleft
impulses across the synaptic cleft

Question 2

2) Neurotransmitters are stored… and are released…20 They diffuse… and… on… 17

Answer 2

in vesicles in the axon endings of the presynaptic neurons and are released on arrival of impulse
across the synaptic cleft and bind to receptors on the membrane of the post synaptic neuron

Question 3

3) A minimum number… to…21

Answer 3

of neurotransmitters must attach to receptors to reach the threshold on the post synaptic membrane to transmit the impulse

Question 4

4) The receptor determines…17

Answer 4

whether the signal is excitatory or inhibitory

Question 5

5) Neurotransmitters must be… to… 21

Answer 5

removed from the cleft straight after the impulse has been transmitted to prevent continuous stimulation of a pathway

Question 6

6) They are removed by:

Answer 6

a) Enzyme degradation
b) Re-uptake

Question 7

a) Enzyme degradation: Neurotransmitters are… and are… (…) 27

Answer 7

broken down into non-active products and are re absorbed by the pre-synaptic neuron where they are resynthesissed into active neurotransmitters (requires ATP)

Question 8

b) Re-uptake: Some of the neurotransmitters.. and is… 26

Answer 8

are reabsorbed directly by the pre synaptic neuron that secreted it and is stored in vesicles ready to be used

Question 9

7) Converging neural pathway allows… 18

Answer 9

the stimulation of weak stimuli that can release enough neurotransmitters to trigger an impulse