unit 3.4: the cells of the nervous system and neurotransmitters at synapses

Question 1

what is the nervous system made up of

Answer 1

nerve cells called neurons

Question 2

what do neuron’s do

Answer 2

transmit electrical signals

Question 3

what are these electrical signals called

Answer 3

nerve impulses

Question 4

what cells support and maintain neurons

Answer 4

glial cells

Question 5

what are the 3 key structures in a neuron

Answer 5

dendrites
cell body
axon

Question 6

what direction to nerve impulses travel

Answer 6

dendrites -> cell body -> axon

Question 7

what is the cell body

Answer 7

contains a nucleus and cytoplasm

Question 8

what is in the cytoplasm of the nerve cell

Answer 8

organelles such as the mitochondria and ribosomes

Question 9

what does the ribosome in the nerve cells do

Answer 9

synthesise proteins (enzymes) for synthesis of neurotransmitters

Question 10

what are dendrites

Answer 10

nerve fibres that carry impulses to the cell body

Question 11

what is the axon

Answer 11

a fibre that carries impulses away from the cell body, covered in a fatty material

Question 12

what is the fatty material surrounding the axon

Answer 12

myelin sheath

Question 13

what do glial cells produce

Answer 13

the myelin sheath

Question 14

what does the myelin sheath do

Answer 14

insulates the axon and speeds up nerve impulse conduction

Question 15

what is myelination

Answer 15

the extent of which the axon is covered by myelin

Question 16

what happens to myelin as a child grows

Answer 16

myelination increases and so does nervous control

Question 17

name a disease that can damage the myelin sheath

Answer 17

Multiple Sclerosis (MS)

Question 18

what happens if the myelin sheath is damaged

Answer 18

can result in a loss of muscular co-ordination

Question 19

what are glial cells 2 functions

Answer 19

maintain and support neuron’s
produce the myelin sheath

Question 20

what are the 3 types of neurons

Answer 20

sensory neuron’s
inter neuron’s
motor neuron’s

Question 21

what is the sensory neuron

Answer 21

has dendrites in contract with receptors in sense organs, these form a myelinated fibre which carries impulses to the cell body, has a short axon which form connections with neuron’s in the CNS

Question 22

what is the inter neuron

Answer 22

connects sensory and motor neuron’s, has may dendrites which form many, complex connections

Question 23

what is the motor neuron

Answer 23

has short dendrites which connect to the neuron’s in the CNS, has a long myelinated axon, axon carried impulses to muscle connection via axon terminals

Question 24

what is a synapse

Answer 24

a gap or space between 2 neurons

Question 25

the neuron before the synapse is called

Answer 25

presynaptic neuron

Question 26

the synapse can also be referred to as the

Answer 26

synaptic cleft

Question 27

the neuron after the synaptic cleft is called

Answer 27

the postsynaptic neuron

Question 28

what travels across the synaptic cleft

Answer 28

neurotransmitters

Question 29

what are the 2 examples of neurotransmitters

Answer 29

acetylcholine noradrenaline (norepinephrine)

Question 30

where are neurotransmitters stored

Answer 30

in vesicles in the axon ending of the presynaptic neuron

Question 31

what happens when a nerve impulse reaches the end of the presynaptic neuron

Answer 31

neurotransmitters are released from the vesicles into the cleft after impulse arrives, they diffuse across the cleft and the neurotransmitters bind to receptors in the membrane of the postsynaptic neuron

Question 32

why are neurotransmitters removed after the impulse has been transmitted

Answer 32

to avoid continuous stimulation

Question 33

what are the 2 ways in which neurotransmitters can be removed from the synaptic cleft

Answer 33

enzyme degradation re-uptake

Question 34

what is enzyme degradation

Answer 34

occurs with acetylcholine, the products are absorbed and used to synthesise new neurotransmitters

Question 35

what is re-uptake

Answer 35

occurs with noradrenaline (norepinephrine), which is reabsorbed by the presynaptic membrane

Question 36

what does continuous synthesis and removal of neurotransmitters require

Answer 36

a large amount of energy/ATP

Question 37

what are the 2 types of signals

Answer 37

excitatory inhibitory

Question 38

what do excitatory signals do

Answer 38

cause increase in action (e.g. cause muscles to contract)

Question 39

what do inhibitory signals do

Answer 39

decreases action (e.g. slows heart rate)

Question 40

what is weak stimuli

Answer 40

when there is not enough neurotransmitters to cause transmission of the nerve impulse

Question 41

what is weak stimuli also known as

Answer 41

sub-threshold stimuli

Question 42

what is summation

Answer 42

the cumulative effect of a series of weak stimuli which triggers an impulse

Question 43

what are endorphins

Answer 43

neurotransmitters that act as natural painkillers by stimulating neurons involved in reducing intensity of pain

Question 44

endorphin production increases in response to

Answer 44

severe injury prolonged and continuous exercise physical & emotional stress certain foods (e.g. chocolate and chilli peppers) eating sex

Question 45

what is dopamine

Answer 45

the neurotransmitter involved in the feeling of pleasure and reinforced particular behaviour

Question 46

name an example of an activity that may activate the reward pathway

Answer 46

eating when hungry

Question 47

what does alzheimer’s disease result in

Answer 47

loss of cells synthesising acetylcholine

Question 48

what is the treatment for alzheimer’s

Answer 48

cholinesterase inhibitors

Question 49

what does parkinson’s result in

Answer 49

loss of dopamine synthesising neurons

Question 50

what is the treatment for parkinson’s

Answer 50

monoamine oxidase inhibitors (MAOIs) and the potential use of adult stem cells

Question 51

what is schizophrenia cause by

Answer 51

overactive dopamine system

Question 52

what treatment can be used for schizophrenia

Answer 52

the use of domaine antagonists

Question 53

what causes general anxiety disorder

Answer 53

imbalance or serotonin and norepinephrine

Question 54

what treatments can be used for anxiety

Answer 54

the use of GABA agonists or beta blockers

Question 55

what causes depression

Answer 55

low levels of serotonin

Question 56

what treatment can be used for depression

Answer 56

norepinephrine re-uptake inhibitors and MAOIs

Question 57

what are the 2 main types of drugs

Answer 57

agonist antagonist

Question 58

what do agonists do

Answer 58

mimic the action of neurotransmitters at synapse and stimulate specific receptors

Question 59

what do antagonists do

Answer 59

bind to specific receptors blocking the action of a neurotransmitter at the synapse

Question 60

how do some other drugs work

Answer 60

by inhibiting the enzymes which degrade neurotransmitters or by inhibiting re-uptake of neurotransmitters at the synapse

Question 61

what can recreational drugs alter in a person

Answer 61

mood (happier/more confident/more aggressive) cognition (become poorer at problem solving and decision making) perception (misinterpretation of colours/sounds/sense of time) behaviour (person can stay awake longer and talk endlessly)

Question 62

what drug type causes addiction

Answer 62

antagonist

Question 63

how antagonists cause drug addiction

Answer 63

increases the number of receptors and increases the sensitivity which gives the individual a craving for the drug

Question 64

what drug type causes tolerance

Answer 64

agonists

Question 65

how do agonists cause drug tolerance

Answer 65

by decreasing the number of receptors and the sensitivity of the receptors, more of the drug is needed to feel the same effect