Neurons (travers) Flashcards

1
Q

Glial cells comprise ___ % of cells in the CNS.

A

90

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2
Q

Schwann cells (in the PNS) and Oligodendrocytes (in the CNS) do what?

A

provide myelination

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3
Q

What is a microglia?

A

It is a macrophage like cell

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4
Q

What does an astrocyte do?

A

It regulates extracellular fluid
Helps form blood brain barrier
Provides neurons with glucose

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5
Q

A Schwann cell and an oligodendrocyte contribute to how many axons?

A

Schwann cell- one axon- many schwann cells per axon

Oligodendrocyte- contributes to many axons

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6
Q

Neurons and microglia interact with each other. What does the neuron do in this relationship?

A

Neurons keep microglia unreactive

Neuronal injury releases ATP, inducing motility

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7
Q

Neurons and microglia interact with each other. What does the microglial cell do in this relationship?

A

Microglia are involved in pruning unused dendrites

Make physical contact with healthy neurons

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8
Q

T/F, proteins and other material can be transported through an axon?

A

True

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9
Q

What facilitates anterograde axonal transport?

A
Microtubules run the length of the axon
Kinesin proteins (motor protein) attached to the microtubule hold and help transport secretory vesicles with necessary material
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10
Q

What is and what facilitates retrograde transport?

A

It is transport from the axon to the cell body.
It is facilitate by dyneins- motor proteins-
Viruses also use this

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11
Q

Tell me about herpes simplex 1

A
  1. Easily transmitted via oral contact
  2. Up to 75% infection in adult population but usually asymptomatic
  3. Virus transmitted retrogradely where it remains latent in trigeminal ganglion
  4. During latency, virus is transcriptionally quiet
  5. In infants virus can go beyond ganglia and cause encephalitis
  6. Can be activated by fever, sun, cold, trauma or stress
  7. Transmitted anterogradely to peripheral tissue, lips, palate causing painful blisters
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12
Q

In the CNS, what happens to damaged neurons?

A

They don’t regenerate
Axons sprout but don’t reach targets
Scar formation prevents axons from reaching targets
Astrocytes make chondroitin sulfate proteoglycans that inhibit neuron growth

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13
Q

In the PNS, what happens to damage neurons?

A

Functional recovery can take place depending on severity

tooth extraction can cause nerve injury

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14
Q

T/F, anterograde degeneration always involves terminal degeneration?

A

True!

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15
Q

What is chromatolysis?

A

It is associated with protein synthesis- cell body swells, eccentric nucleus

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16
Q

If a nerve cell is damage in the PNS, what do Schwann cells do?

A

They proliferate and produce laminin for substrate for the regenerating axons
Schwann cells secrete NGF (nerve growth factor)
NGF is transported to the ganglion cell body

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17
Q

What does NGF do?

A

It regulates the gene expression and promises sprouting

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18
Q

NGF travels via retrograde or anterograde transport?

A

Retrograde

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19
Q

T/F adjacent axons can sprout and go to the target of a degenerating axon terminal?

A

True!

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20
Q

Collateral sprouting is great.

A

Indeed

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21
Q

T/F Reinnervation does not occur humans.

A

True

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22
Q

In order for synaptic vesicles to release their contents, what two molecules are vital?

A

Calcium and synaptotagmin

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23
Q

With the post synaptic potential, what is temporal summation? What is spacial summation?

A

Temporal summation is where the PSP’s are close enough together in time to be additive.
Spatial summation is where two different impulses come at the same time, but at different places- also additive

24
Q

What is a classic neurotransmitter?

A

Released from presynaptic terminal due to the arrival of an action potential- it functions in rapid communication and it acts on postsynaptic cells to produce an excitatory or inhibitory post synaptic potential

25
Q

What is a neuromodulator?

A

Often co-released with neurotransmitters.
May act to postsynaptically amplify or dampen current synaptic activity
Can act on the presynaptic cell to alter synthesis, release, or uptake of neurotransmitters
Actions can involve changes in protein synthesis or enzyme activity, so it can be a lot slower, taking minutes or days

26
Q

Tell me about acetylcholine.

A

It is synthesized from choline and acetyl Co-enzyme A by choline acetyltransferase in synaptic terminal

Its action is stopped by diffusion & degradation (by acetylcholinesterase)

Choline re-uptake by presynaptic neuron

27
Q

What are some neurons that release Ach?

A

Motor neurons
Neurons in nucleus basalis and pons
Preganglionic sympathetic and parasympathetic neurons
All postganglionic parasympathetic neurons

28
Q

What are acetylcholine receptors?

A

Muscarinic receptors- mostly found in CNS, but also in salivary glands

Nicotinic receptors

29
Q

What is Myasthenia gravis?

A

It’s an autoimmune disorder in which the individual makes antibodies to nicotinic receptors
Muscle weakness results.

30
Q

How is M. gravis treated?

A

Acetylcholininsterase inhibitors

31
Q

Biogenic amines are synthesized from what?

A

amino acids

32
Q

T/F Catecholamines include dopamine, norepinephrine and epinephrine?

A

True

33
Q

Catecholamines are original synthesized from which amino acid?

A

Tyrosine

34
Q

What is the catecholamine life cycle?

A
  1. Synthesis occurs in the presynaptic terminal and stored in vesicles
  2. Release is Ca++ dependent
  3. Termination of action occurs via enzymatic degradation and presynaptic neuron re-uptake
35
Q

T/F neurons that synthesize catecholamines are found in very limited locations, but the receptors for the ligand are found extensively throughout the CNS?

A

True

36
Q

What is a possible side effect of people who receive dopamine blocking drugs?

A

Tardive dyskinesia (think parkinsons shakiness and stuff, except for with you mouth and tongue)

37
Q

Serotonin is synthesized from what amino acid?

A

Tryptophan- think sleep after eating a whole turkey.. much like this class. I feel like I just ate a whole turkey

38
Q

Histamine is derived from histadine

A

Yep

39
Q

What are the excitatory amino acids?

A

Glutamate and aspartate

40
Q

Excitatory amino acids bind what type of receptor?

A

Ionotropic

41
Q

Tell me about the NMDA receptor

A

Involved with long term change- functions that last like memory formation or chronic pain
Excessive excitation will result in cell death- epilepsy, trauma, stroke
Neuron death occurs from Ca concentration reaching toxic levels

42
Q

How is glutamate controlled in the synapse so that overstimulation doesn’t occur?

A

When glutamate is in the synaptic cleft, it is removed by astrocytes.
Glutamate is transported into the astrocyte where it is converted into glutamine, which is then released back into extracellular space where the presynaptic terminal takes it up again and makes more glutamine

43
Q

What is excitotoxicity?

A

It is where excessive excitation leads to cell death- epilepsy, trauma, stroke

44
Q

What factors promote long term potentiation?

A

The NMDA receptor is phosphorylated (permanent removal of Mg+ block)
Calcium entry into the cell via the NMDA receptor leads to the phosphorylation of and increase in the number of AMPA receptors

45
Q

What is long term potentiation?

A

When a function lasts a long time and synapses are almost continual

46
Q

GABA is a(n) _________ neurotransmitter.
GABAa opens which channel?
GABAb opens which channel?

A

inhibitory
Cl-
K+

47
Q

GABA deficiency is linked to what disease?

A

Huntington chorea

48
Q

Glycine is a(n) ________ neurotransmitter.

It opens what channel?

A

inhibitor

Cl-

49
Q

What do peptides do?

A

They function as neuromodulators

50
Q

Do peptides have a short or long effectiveness?

How is their action terminated?

A

They can last a long time.

Proteolysis and diffusion stop the action

51
Q

Where are peptides synthesized?

A

In the soma

52
Q

Nitric oxide (NO) is a liquid/solid/gas?
It is/isn’t stored in vesicles?
It is/isn’t freely diffusible across the membrane (no synapse required)?

A

Gas
Isn’t stored in vesicles
Is freely diffusible

53
Q

T/F- ATP is both an energy source and a neurotransmitter?

A

True

54
Q

T/F- ATP as a neurotransmitter is usually excitatory.

A

True

55
Q

What are some possible actions of drugs on a synapse?

A

Increase transmitter into cleft
Block transmitter release
Modulate transmitter synthesis
Block transmitter repute
Block enzymes that metabolize transmitter
Bind to postsynaptic ionotropic receptor
Bind to the postsynaptic G-protein coupled receptors