synaptic transmission

Question 1

summarise the process of neurotransmitters being released into the synapse

Answer 1

• action potential moves down axon terminal of presynaptic neuron
• calcium channels open
• terminal button is flooded with calcium ions
• vesicles containing neurotransmitters are released and travel down outer membrane of terminal button
• vesicle casing fuses with membrane
• neurotransmitter is released from vesicles into synaptic cleft

Question 2

summarise the process of neurotransmitters being transmitted to post synaptic neuron

Answer 2

• receptors on post synaptic neuron are designed to bind to a specific neurotransmitter
• when they detect it, the neurotransmitter molecule is absorbed by the post synaptic neuron
• neurotransmitters not absorbed are reabsorbed by presynaptic neuron or destroyed by enzymes
• reabsorbed are destroyed by enzymes in neuron to prepare for future action potential

Question 3

describe seratonin

Answer 3

neurotransmitter
- happiness and good mood
- regulates sleep wake cycle with melatonin
- low levels link to depression and anxiety
- selective seratonin reuptake inhibitors prescribed for mental disorders

Question 4

describe dopamine

Answer 4

neurotransmitter
- produces pleasure when reward pathway is activated
- memory, learning, movement

Question 5

describe endorphins

Answer 5

neurotransmitter
- relieves pain and stress
- during pleasurable activities

Question 6

what is an excitatory inhibitor?

Answer 6

generates action potential in receiving neuron

Question 7

what is an inhibitory inhibitor?

Answer 7

prevents action potential being generated

Question 8

strength PEE
- supporting evidence O

Answer 8

a strength of the CNS as an explanation is supporting evidence from Owens. for example, the use of post mortem examinations showed that schizophrenics have an excess number of dopamine receptors in the cerebral cortex. therefore, they are more sensitive to the action of dopamine than non sufferers.

Question 9

weakness PEE
- opposing study

Answer 9

a weakness of the CNS as an explanation is rejecting evidence from Allen and Stevens. for example, synaptic transmission involving hippocampal neurons were found to be unreliable. less than half the neurotransmitters arriving from the pre synaptic neuron were picked up by the post synaptic neuron.

Question 10

strength PEE
- supporting evidence J

Answer 10

a strength of the CNS as an explanation is supporting evidence from Jovanovic who used PET scans to research women’s seratonin. those without pre menstrual dysphoric disorder showed differences in seratonin in the synaptic receptors compared to a control group. therefore, this shows that seratonin levels are linked to depression and low mood.

Question 11

weakness PEE
- criticism of methodology

Answer 11

a weakness of the CNS as an explanation is that much of the evidence about synaptic transmission has come from studies with animals where lesions can be made. it is difficult to generalise animal brains to humans as humans are different considering the conscious and emotional functioning which is more complex.

Question 12

strength PEE
- compliment of methodology

Answer 12

a strength of the CNS as an explanation is that brain scanning is a reliable method. for example, humans can be used in research, and actual brain activity/structures can be produced in research. therefore, the method has scientific credibility as it has objective measures and is used more often so consistency of results can be checked.