synaptic transmission

Question 1

synaptic transmission

Answer 1

the process in which neighbouring neurones communicate by sending neurotransmitters across the synapse

Question 2

neurotransmitter

Answer 2

chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another

Question 3

neurotransmitters can be

Answer 3

excitatory or inhibitory

Question 4

excitatory neurotransmitters

Answer 4

make the post synaptic neurone more likely to fire

Question 5

inhibitory neurotransmitter

Answer 5

make the post synaptic neurone less likely to fire

Question 6

excitatory neurotransmitter example

Answer 6

noradrenaline

Question 7

inhibitory neurotransmitter example

Answer 7

GABA

Question 8

what is summation

Answer 8

the net effect of the excitatory and inhibitory post synaptic potentials - adding up positive and negative charges

Question 9

explain process of synaptic transmission (4 marks)

Answer 9

• electrical impulses reach presynaptic terminal
• electrical impulses trigger release of neurotransmitters
• neurotransmitters cross synapse from vesicles
• neurotransmitters combine with receptors on post synaptic membrane
• stimulation of post synaptic receptors by neurotransmitters result in either excitation or inhibition of post synaptic membrane

Question 10

explain why neurones can only transmit information in one direction at a synapse

Answer 10

• the synaptic vesicles containing the neurotransmitter are only present on the presynaptic membrane
• neurotransmitters are only released from the presynaptic membrane
• the receptors for the neurotransmitters are only present on the post synaptic membrane
• its the binding of the neurotransmitters to the receptor which enables the signal to be transmitted onto the next neurone

Question 11

briefly outline how excitation and inhibition are involved in synaptic transmission

Answer 11

• neurotransmitters can be either excitatory or inhibitory
• if the neurotransmitter is excitatory then the post synaptic membrane is more likely to fire an impulse
• if the neurotransmitter is inhibitory then the post synaptic membrane is less likely to fire an impulse
• the E and I influences are summed if the net effect is inhibitory the post synaptic membrane is less likely to fire, if the net effect is excitatory the PSM is more likely to fire