c2.2 neural signalling

Question 1

neurone

Answer 1

cell within the nervous system that carry electrical impulses

Question 2

sensory neurone function

Answer 2

1. sense stimuli
2. send to spine

Question 3

sensory neurone shape

Answer 3

cell body at the end

Question 4

relay neurone function

Answer 4

travel

Question 5

motor neurone function

Answer 5

move

Question 6

what allows electrical impulses to be faster

Answer 6

myelin sheath

Question 7

how does myelin sheath allow electrical impulses to be faster

Answer 7

reduce distance electrical impulse has to travel so the speed is much faster

Question 8

location of the myelin sheath

Answer 8

layers surrounding the axon

Question 9

how is an impulse generated + how does it travel [3]

Answer 9

1. part of axon going thru action potential, the rest is at resting potential
2. electrical impulse will cause resting potential to turn into action potential
3. the action potential will trigger a new action potential in the adjacent section of the axon in one direction
   
   • previous part of action potential will go back to resting

Question 10

why cant the electrical impulse go back

Answer 10

-80mV too negative so sodium voltage gated channel cant open (hyperpolarisation)

Question 11

synapse

Answer 11

junction between 2 neurones in the nervous system

Question 12

what can synapse be in between [2]

Answer 12

1. between sensory receptor cells and neurones
2. between neurones and muscle fibre or glands

Question 13

acetylcholine released by + function

Answer 13

being released by motor neurones to control muscle contraction

Question 14

what happens to acetylcholine once it activates the action potential

Answer 14

recycled and broken down

Question 15

what happens if acetylcholine is not broken down

Answer 15

muscle spasms

Question 16

characteristic of acetylcholine

Answer 16

can bind to completely different receptors

Question 17

why can acetylcholine bind to 2 completely different receptors

Answer 17

made up of 2 parts: acetyl CoA and choline
- so head and tail are diff shapes

Question 18

enzyme that breaks down acetylcholine

Answer 18

acetylcholinesterase

Question 19

why does the electrical current only go one way during depolarisation

Answer 19

the one before is at hyperpolarisation (-80mV) but the one next is at -70 mV so its easier to get the -70mV up to action potential

Question 20

what is depolarisation caused by

Answer 20

sodium ions rushing in

Question 21

what is repolarisation caused by

Answer 21

potassium ions rushing out

Question 22

what is the node of revere

Answer 22

gaps between the myelin sheath

Question 23

why are gaps between the myelin sheath needed

Answer 23

insulation prevent ions movement

Question 24

how do gaps between the myelin sheath cause the distance travelled reduced

Answer 24

reduces ion exchange so ion exchange only happens at the nodes and less energy is required

Question 25

exogenous chemical

Answer 25

enters the body of an organism from an outside source eg. through the skin, lungs, gut

Question 26

function of neonicotinoids

Answer 26

blocks synaptic transmission

Question 27

how does neonicotinoids block synaptic transmission

Answer 27

binds to the acetylcholine receptor in the cholinergic synapses in the central nervous system of insects

Question 28

why is the binding of neonicotinoids to cholinergic synapses irreversible

Answer 28

acetylcholinesterase doesnt break down neonicotinoids

Question 29

how does neonicotinoids cause death to an insect

Answer 29

blocks their receptors bc binding between neonicotinoids to cholinergic synapses are irreversible

Question 30

why doesnt neonicotinoids affect humans [2]

Answer 30

1. fewer receptors 2. binding not as strong

Question 31

function of cocaine

Answer 31

promotes synaptic transmission

Question 32

role of cocaine

Answer 32

acts at synapses that use dopamine as neurotransmitter

Question 33

mechanism of cocaine

Answer 33

1. binds to dopamine reuptake transporters in the presynaptic neurone 2. dopamine builds up in the synaptic gap → postsynaptic neurone is continuously excited

Question 34

what are dopamine reuptake transporters

Answer 34

membrane proteins that pump dopamine back into the presynaptic neurone

Question 35

temporal summation

Answer 35

multiple firing form one input

Question 36

why is temporal summation needed

Answer 36

might have to fire more than once to hit the threshold

Question 37

spacial summation

Answer 37

all or nothing - add all five synaptic neurone then decides activity

Question 38

2 types of spacial summation

Answer 38

1. excitatory 2. inhibitory

Question 39

excitatory neurotransmitters function

Answer 39

excites post-synaptic neurone to cause depolarisation

Question 40

excitatory neurotransmitters summation

Answer 40

leads to EPSPs (excitatory post-synaptic potentials)

Question 41

inhibitory neurotransmitters function

Answer 41

inhibits post-synaptic neurones by causing hyperpolarisation

Question 42

inhibitory neurotransmitters summation

Answer 42

leads to IPSPs (inhibitory post-synaptic potentials)

Question 43

inhibitory neurotransmitters egs

Answer 43

anaesthesia

Question 44

mechanism for perception of pain [2]

Answer 44

1. free nerve endings in the skin have channels for positively charged ions that respond to stimuli 2. entry of positively charged ions will cause threshold potential to be reached and the nerve impulse will be passed to the brain and perceived as pain

Question 45

consciousness

Answer 45

property that emerges from the interaction of individual neurones in the brain

Question 46

consequences of interaction eg

Answer 46

emergent properties- consciousness