Neurotransmission and treatments for depression Flashcards

Communication in the brain

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1
Q

What are different cells of the nervous system?

A

Neurons and Glial cells

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2
Q

What percentage of the volume do Glial cells make up of the CNS?

A

50%

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3
Q

What function do the Glial cells have in the CNS?

A

Maintenance of synapses through the production of myelin and provide nourishment for the neurons

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4
Q

What are the three major structures of the Neuron?

A

Cell body, Dendrites, Myelin sheath

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5
Q

What is in the Neuron cell body?

A

Contains all of the organelles which maintain the cell, includes the nucleus (contains all of the genetic material)

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6
Q

What is the function of the cell body?

A

Relays signals down to the axon

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7
Q

What is the structure of dendrite?

A

Thin, bushy like structures, specialised projections that can receive signals from neighbouring neurons

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8
Q

What are the functions of the dendrites?

A

Receiving signals from neighbouring neurons and relaying information into the cell body

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9
Q

What is the structure of the myelin sheath?

A

80% lipids (fats) and 20% proteins

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10
Q

What is the function of the myelin sheath?

A

Insulating the neurons so that electrical signals are not lost

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11
Q

What makes the myelin sheath?

A

Oligodendrocytes in the CNS

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12
Q

What does gray matter mostly consist of?

A

Neuronal cell bodies

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13
Q

What does white matter mostly consist of?

A

myelinated axons

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14
Q

Where are neuronal cell bodies most abundant?

A

Cerebrum, brain stem and cerebellum

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15
Q

What percentage of the brain volume does the cerebellum make up?

A

10%

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16
Q

What is special about the cerebellum?

A

It contains more neurons than the rest of the brain put together

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17
Q

Where is gray matter usually found?

A

Gray matter is usually found surrounding white matter in the external areas of the brain

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18
Q

What does the term nuclei refer to?

A

The regions of gray matter that are located in deeper regions of the brain

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19
Q

In the cerebrum and cerebellum where is white matter more likely to be found?

A

Predominantly found in deeper areas

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20
Q

What are other gray matter structures?

A

Basal ganglia

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21
Q

In what is the basal ganglia embedded in?

A

In white matter

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22
Q

In which case is the gray matter is embedded into the white matter?

A

In the spinal cord <3

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23
Q

Are neuron electrically excitable?

A

Yes

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24
Q

What concentration of ions differ from the inside the cells?

A

Sodium (NA+) and potassium (K+)

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25
Q

Which elements start off outside the cell?

A

Sodium

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26
Q

What causes the ions to continuously move down the concentration gradient?

A

The concentration differences cause ions to continuously move down the concentration gradient through ion channels that are high permeable

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27
Q

Which ion is the channel highly permeable to?

A

Potassium (K+)

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28
Q

If the movement stops with the inside of the cell what will be the resting potential of the cell?

A

-70mV

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29
Q

What is an action potential?

A

A short term change in the electrical potential that travels along a cell it releases the neurotransmitter into the synaptic cleft

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30
Q

What is the resting potential?

A

Is what happens when a neurons is at rest

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31
Q

What is an action potential is caused by?

A

Different ions crossing the neuron membrane resulting in the neuron sending information down the axon, away from the cell body

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32
Q

What is an action potential?

A

An explosion of electrical activity that is created by a depolarising current

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33
Q

How many steps can the formation of action potential be divided into?

A

five steps

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34
Q

What are the 5 steps involved in making an action potential

A

1) A stimulus from a sensory cell or another neuron causes the target cell to depolarise toward the threshold potential
2) If the threshold of excitation is reached, all sodium channels open and the membrane depolarise
3) At the peak action potassium channels open and K+ begins to leave the cell, at the same time sodium channels close
4) The membrane becomes hyperpolarized as potassium ions continue to leave the cells. The hyperpolarised membrane is in a refractory period and cannot fire
5) The potassium channels close and the sodium transporters restores the resting potential

35
Q

What is the All or nothing principal?

A

If the neurons do not reach this critical threshold level then non action potential will fire

36
Q

What does it mean when there are no big or small action potential?

A

It means that that action potential can only happen when the meet a certain threshold of excitation thus all action potentials are the same

37
Q

What are the components of the structure of the synapse?

A

Synapse and axon terminals, and dendrites

38
Q

Describe synaptic transmission

A

The neurotransmitters diffuse out of the synaptic vesicles and into the synaptic gap, the neurotransmitter usually have a summination of either -1/+1 which means they either have an excitatory or inhibitory effect. They then bind to the specialised receptor site where they are reabsorbed and resused

39
Q

What is spatial summination?

A

Adds together all inputs received at the same time

40
Q

What is temporal summination?

A

Adds together the inputs in the same place but slightly different times

41
Q

What is a signal termination?

A

The synaptic cleft is cleared

42
Q

How is the synaptic cleft cleared?

A

Neurotransmitter may be broken down my an enzyme, may be sucked back into the pre-synapse or simply diffused, could also be mopped up by glial cells

43
Q

What is a neurotransmitter?

A

A chemical messenger that transmits signals from a neuron to a target cell across the synapse

44
Q

What are the potential targets for neurotransmitters?

A

Neurons, another type of cell such as muscle or gland cells

45
Q

Where are neurotransmitters held?

A

Synaptic vesicles of the pre-synaptic cell

46
Q

What a Ligand Gated Ion Channels?

A

A simplistic gated transmitter site

47
Q

How does the gated mechanism work in the Ligand Gated Channel?

A

The ion binds to the specialised receptor sites and then the gated channel opens up which induces ion fluxes

48
Q

What is the G protein coupled receptor?

A

The neurotransmitter binds to the receptor site which cause the the G protein to release and trigger gate open and trigger the release of enzymes

49
Q

What is the difference between the ion gated channel and the G protein receptor?

A

Ion gated is a lot simpler mechanism than g protein

50
Q

What is another difference between Ion gated channel and Metabotropic receptors?

A

Metabotropic receptors are less direct so their reactions are slower.

51
Q

What are the two types of neurotransmitters?

A

Inhibitory and Excitatory

52
Q

What is an inhibitory neurotransmitter?

A

They have an inhibitory effect on the neuron and decrease the likelihood that the neuron will fire an action potential

53
Q

What is an excitatory neurotransmitters?

A

They have an excitatory effect on the neurons. This means that they increase the likelihood that the neuron will neurons will fire an action potential.

54
Q

List the excitatory neurotransmitters?

A

Glutamate, Acetylcholine, Histamine, Dopamine, Norepinephrine, Epinephrine

55
Q

List the inhibitory neurotransmitters?

A

Gamma-Aminobutyric acid, Serotonin, Dopamine

56
Q

List the neuromodulators

A

Dopamine, Serotonin, Acetylcholine, Histamine, Norepinephrine

57
Q

What is the chief neurotransmitter of the parasympathetic nervous system?

A

Acetylcholine

58
Q

What the neurotransmitter Acetylcholine responsible for?

A

Plays a role in memory, learning, attention, arousal and involuntary muscle movement

59
Q

What medical condition is associated with low levels of Acetylcholine?

A

Alzheimer’s disease

60
Q

What is the function of Acetylcholine?

A

Helps send messages between nerve cells

61
Q

Why is it important to have a higher concentration of Acetylcholine?

A

Leads to better communication in the brain

62
Q

What medications can ease symptoms of Alzheimer’s disease for a while?

A

Donepezil, rivastigmine and galantamine

63
Q

How do Donepezil, rivastigmine and galantamine ease symptoms of Alzheimer’s disease?

A

Prevent the enzyme called acetylcholinesterase from breaking down acetylcholine

64
Q

Where are amino acid neurotransmitters common?

A

In the central nervous system

65
Q

What are the amino acid neurotransmitters?

A

Glycine, glutamate and GABA

66
Q

What is Glutamate?

A

The most abundant excitatory neurotransmitter

67
Q

Is glutamate limited to binding to a specific receptor?

A

No it can bind to a range of different receptor sites

68
Q

What does glutamate have implication on?

A

Learning and memory

69
Q

What does any dysfunction in the glutamate neurotransmitter have an effect on?

A

Propose to play a role in schizophrenia

70
Q

Which is the most abundant inhibitory neurotransmitter?

A

GABA

71
Q

What neurotransmitter is Glycine?

A

A co-agonist

72
Q

What is an agonist?

A

A substance that mimics the actions of neurotransmitter or hormone to produce the same response from the target receptor

73
Q

Examples of Monoamines

A

catecholamines, epinephrine, norepinephrine, dopamine, Indolamine

74
Q

What function does catecholamines have?

A

Helps the body respond to stress and prepare the body for flight or flight reactions

75
Q

What function does epinephrine have?

A

It is both a neurotransmitter and a hormone. As a neurotransmitter it aids communication in the brain. As a hormone it aids the function of the adrenal gland.

76
Q

What other monoamine functions as both a hormone and neurotransmitter?

A

Norepinephrine

77
Q

What function does norepinephrine have as a neurotransmitter?

A

Plays a role in the sleep- wake cycle, helping you wake up, increasing attention and focus on preforming a task and in memory storage.

78
Q

What function does dopamine have?

A

It is important in executive function, motor control, motivation, reinforcement and reward

79
Q

What is the function of Indolamines

A

Helps with sleeping, eating and digestion

80
Q

What are the three treatment methods for Depression?

A

Tricyclics, MAOIs, SSRI’s

81
Q

Why are tricyclic and SSRI’s considered similar treatment methods?

A

Because they both block the reuptake of serotonin how tricyclics also block the reuptake of norepinephrine

82
Q

What gives MAOI’s it s anti-depressant effect?

A

It prevents the enzyme called monoamine oxidase is involved in removing the neurotransmitters norepinephrine, serotonin and dopamine which means there is a greater concentration of these neurotransmitters in the brain.

83
Q

What are condition associated with lower concentrations of dopamine?

A

Parkinson’s Disease, restless leg syndrome, Depression, Schizophrenia, ADHD