EX1; Cell Communication Flashcards

1
Q

Neurons make up what percentage of CNS cells

A

10%

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2
Q

What are the 3 main parts of a neuron

A

soma; containing the nucleus; protein synthesis
dendrites; major input processes (respond with graded potentials)
axon; output processes for signaling (action potentials)

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3
Q

This is the initial segment of a neuron; the trigger zone for action potentials

A

axon hillock

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4
Q

This part of the axon is used for vesicle storage

A

axon terminals

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5
Q

This type of neuron is a sensory/input neuron; transmit information to CNS; the bodies lie outside the CND in ganglia

A

afferent neuron

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6
Q

This type of neuron is motor/output; transmits commands to effector cells; bodies lie within CNS but axons project outside

A

efferent neurons

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7
Q

This type of neuron is located within the CNS; functions as integrators and switches

A

interneurons

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8
Q

What percentage of the CNS do glial cells make up

A

90%

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9
Q

Which undergoes cell division, neurons or glial cells

A

glial cells

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10
Q

What are the two types of myelinating glia

A

PNS; Schwann cells (one axon)

CNS; oligodendrocytes (many axons)

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11
Q

These are macrophage-like glial cells and can be in either unreactive or reactive

A

microglia

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12
Q

These glial cells regulate ECF, provide neurons metabolically, and surround brain capillaries forming the blood brain barrier

A

astrocytes

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13
Q

This provides movement of proteins and other material from one part of neuron to another

A

microtubules

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14
Q

What are the two types of microtubule transport

A

anterograde

retrograde

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15
Q

This type of transport is from cell body toward terminal

A

anterograde

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16
Q

What type of motor protein is required for anterograde transport, and what are the speeds of it

A

kinesins
fast transport for organelles such as neurotransmitter vesicles
slow transpire for structural proteins

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17
Q

This type of transport is from axon terminal towards cell body

A

retrograde

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18
Q

What type of motor protein is required for retrograde transport and it moves what

A

dyneins

fast transport of things like growth factors and also viruses

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19
Q

This virus is easily transmitted through oral contact and is transmitted retrogradely where it remains latent in the trigeminal ganglion

A

herpes simplex virus type 1

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20
Q

True or False

Damaged CNS neurons regenerate

A

False; they do not

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21
Q

CNS axons do this, but do not reach targets

A

sprout

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22
Q

This prevents surviving CNS axons from reaching targets

A

scar formation

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23
Q

Astrocytes make this that inhibits neuron growth

A

chondroitin sulfate proteoglycans

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24
Q

This is clinically signifiant; dental procedures (extractions) can cause nerve damage

A

PNS

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25
Q

True or False

functional recovery of the PNC can take place depending on the severity

A

True

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26
Q

This is associate with protein synthesis; cell body swells, eccentric nucleus

A

chromatolysis

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27
Q

What becomes of a neuron in response to a severe nerve injury

A

terminal degeneration
transganglionic degeneration
transynaptic degeneration

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28
Q

What becomes of a neuron in response to a less severe injury

A

anterograde degeneration

injured cell nucleus (chromatolysis)

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29
Q

These cells produce laminin for substrate for regenerating axons and nerve growth factor (NGF)

A

Schwann cells

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30
Q

This regulates gene expression and promotes sprouting

A

NGF

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31
Q

What are the specific components NGF is involved with

A

microtubules and microfilaments
neurotransmitter production
ion channels
neurotransmitter receptors

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32
Q

Collateral sprouting explains what when there is ipsilateral removal of trigeminal nerve leaving once side anesthetic

A

crossed-midline sensitivity

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33
Q

This is an anatomically specialized junction between a neuron and another cell at which the electrical activity of the presynaptic neuron influences the electrical activity in the post synaptic cell

A

synapse

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34
Q

What are the four types of synapses

A

chemical vs electrical

excitatory vs inhibitory

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35
Q

What are the three types of chemical synpases

A

axo-somatic
axo-dendritic
axo-axonis

36
Q

Where are the three location of receptors

A

postsynaptic
presynaptic
autoreceptors

37
Q

What are the 6 steps of synaptic transmission

A
  1. action potential reaches terminal
  2. voltage-gated Ca channels open
  3. calcium enters axon terminal
  4. neurotransmitter is released and diffused into the cleft
  5. neurotransmitter binds to post synaptic receptors
  6. neurotransmitter removed from synaptic cleft
38
Q

A post-synaptic potential is only how many mVs

A

0.5mV

39
Q

What determines if a threshold is reached of a PSP

A

the combined effect to excitatory or inhibitory synaptic input

40
Q

This is the adding together of PSPs from one synaptic contract (over time)

A

temporal summation

41
Q

This is adding together of PSPs produced by different synapses

A

spatial summation

42
Q

At which type of sites can drugs interact with the synaptic junction

A

a whole bunch of different places

43
Q

This functions in rapid communication and acts on postsynaptic cell to produce EPSP or IPSP (excitatory or inhibitory)

A

classical neurotransmitter

44
Q

This may act postsynaptically to amplify or dampen on-going synaptic activity or may act on pre-synaptic cell to alter synthesis, release, uptake, or metabolism of neurotransmitters

A

neuromodulators

45
Q

Actions of neuromodulators includes what

A

changes in DNA/protein synthesis or enzyme activity; can thus be much slower in action (min-days)

46
Q

This is synthesized from choline and acetyl in the synaptic terminal; action stopped by diffusion and degration

A

acetylcholine

47
Q

What is choline re-uptakes by

A

presynaptic neuron

48
Q

What are four examples of neurons that release ACh

A

motor neurons
neurons in nuclus basalis and pons
all preganglionic neurons
all postganglionic parasympathetic neurons

49
Q

Where are two locations of ACh neurons in the CNS

A

basal forebrain

pontine nuclei

50
Q

These ACh receptors are mostly found in the CNS but also in parasympathetic postganglionic synapse (salivary glands)

A

muscarinic receptors

51
Q

The binding of ACh in muscarinic receptors triggers what

A

G protein that either open or closes ion channels

depolarizing or hyperpolarizing

52
Q

Muscarinic receptors are blocked by what

A

atropine

53
Q

These ACh receptors are few in the CNS

A

nicotinic receptor

54
Q

ACh binding in nicotinic receptors triggers what

A

opening ion channels with the receptor

depolarizing

55
Q

Nicotinic receptors are blocked by what

A

curare (e.g. neuromuscular junction)

56
Q

This ACh disease is an autoimmune disease in which individuals make autoantibodies to nicotinic receptors; muscle weakness; treated with acetylcholinisterase inhibitors

A

myasthenia gravis

57
Q

This ACh is a common form of dementia, loss of neurons in the nucleus basal is leading to decrease in cholinergic activity in cortex

A

alzheimers disease

58
Q

This is synthesized from amino acids, specifically tyrosine

A

catecholamines

59
Q

What is the life cycle (3 steps) of catecholamines

A
  1. synthesis in presynaptic terminal; stored in vesicles
  2. release is Ca dependent
  3. termination of action; presynaptic neuron re-uptake and degradation (MAO)
60
Q

True or False

Neurons that synthesize catecholamines are found through the CNS

A

False; the neurons are only found in very limited locations

61
Q

True or False

receptors for catecholamines are found extensively throughout the CNS

A

True

62
Q

What are the type of catecholamines receptors

A

G-protein coupled receptors

63
Q

True or False

Catecholamine is involved with only a few functions and dysfunctions

A

False; it is involved with many

64
Q

This is synthesized in the pre-synaptic terminal and is found in specific areas of the midbrain and brainstem

A

dopamine

65
Q

The two main groups of dopamine G-protien receptors are D1 and D2; what are their functions

A

D1 - activate adenylate cyclase

D2 - inhibit adenylate cyclase (leading to hyperpolarization)

66
Q

This disorder involves the D2 receptors being impaired, commonly presented with rhythmic oral movements

A

tardive dyskinesia

67
Q

This is found in locus ceruleus (attention/sleep) and other brainstem groups with autonomic and homeostatic functions and is often referred to as noradrenaline and adrenaline

A

norepinephrine and epinephrine

68
Q

norepinephrine neurons include what

A

sympathetic postganglionic neurons and some CNS

69
Q

epinephrine neurons include what

A

adrenal gland as circulating hormone (not much in CNS)

70
Q

These are G protein coupled receptors involving NE

A

noradrenergic receptors

71
Q

What are the functions of α receptors (α1 and α2) involving NE

A

α1; intracellular release of Ca; excitatory

α2; inhibitory via opening of K channels or blocking Ca

72
Q

What is the function of β receptors ( β1, β2, β3) involving NE

A

open Ca channels

73
Q

This is synthesized from tryptophan and is found in the rostral raphe nucleus (sleep, mood, homeostatic function) and the caudal raphe nuclei (sensori-motor function) and uses G protein coupled receptors

A

serotonin

74
Q

What is the function of serotonin

A

may different functions ranging from sensrimotor systems to cognitive function (mood)

75
Q

This is found only in a small population of hypothalamic neurons involved in sleep-wakefulness; G-protein coupled receptors

A

histamine (derived from histidine)

76
Q

This is the most common excitatory amino acid (the other is aspartate)

A

glutamate

77
Q

The excitatory amino acids bind several classes of what

A

ionotropic receptors; have channels permeable to Na, K, and Ca
aslo binds to metabotropic receptors (G-protein)

78
Q

This is involved with functions that last (memory, chronic pain, etc.); excitotoxcitiy; excessive excitation causes neuron death from Ca reading toxic levels

A

NMDA (n-methyl-D-asparate) receptor

79
Q

NMDA receptors are involved in the synaptic mechanism of what

A

long term potentiation

80
Q

What are two factors promoting long ted potentiation

A

phosphorylation of NMDA receptor

calcium entry into cell via NMDA; phosphorylation of AMPA and an increased number, synthesis of retrograde nitric oxide

81
Q

This is a major inhibitory neurotransmitter in the CNS, modified form of glutamate of which can form Huntington chorea, form of motor spasticity

A

GABA (gamma-amminobutyric acid)

82
Q

GABA (A) is an ionotropic receptor that opens what

A

Cl channels

83
Q

GABA (B) is a metabotropic receptor that opens what

A

K channels

84
Q

glycine is an inhibitory neurotransmitter in the spinal cord that does what

A

receptor opens Cl channels

blocked by strychnine

85
Q

There are over 80 of these identified and are often co-released with neurotransmitters (synthesized in stroma and must be transported to be released) can function as a neuromodulator, and its action can last a long time terminated by proteolysis and diffusions

A

peptides

86
Q

This is a gas transmitter that can modulate neurotransmitter release, plays a role in numerous brain functions and has an excitotoxicity role in injuries

A

nitric oxide

87
Q

This is usually an excitatory (taste) transmitter usually co-release with classical neurotransmitters

A

ATP