Nerve Flashcards

1
Q

What are the 2 major types of glia?

A
  1. microglia = immune cells of the CNS
  2. Macroglia
    a. Oligodendrocytes: in the gray matter, helps with neuron supports. Acts like myelin in white matter
    b. Schwann Cells: provides myelin for the PNS
    c. Astrocytes:
    • Fibrous: intermediate filaments, mostly in white matter
      • Protoplasmic: mostly in gray matter, sends processes to blood vessels, forms the Blood-Brain-Barrier. Also produces tropic substances and maintain ion concentration
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2
Q

What are the components of a neuron?

A
  1. cell body = has a nucleus, where metabolic processes happen
  2. dendrites = branches out from cell body; receives impulses from other cells
  3. axons = originates from axon hillock from the cell body
    - Initial segment: first portion
    - Divides into presynaptic terminals
    - Ends in terminal buttons (boutons) –> contains vesicles or granules of synaptic transmitters
  4. +/- myelin
  5. in between each myelin = nodes of Ranvier
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3
Q

What’s myelin?

A

protein-lipid complex that’s wrapped up around an axon
- Compaction of the myelin sheaths occurs when the extracellular portion of the protein P0 is locked to the extracellular P0 of the opposing membrane
- Speeds up nerve conduction –> travels at nodes of Ranvier rather than along the axon

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4
Q

What is orthograde axonal trasnport?

A

going from the cell body towards axon
- occurs along microtubules
- needs dynein and kinesin
- has both fast and slow components

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5
Q

What’s retrograde axonal trasnport?

A

going from the axon twaords the cell body
- also occurs along microtubules
about 200mm/day
ex. nerve growth factor (NGF)

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6
Q

What’s the function of neurotrophins?

A

it’s associated with neuronal development, growth, and survival

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7
Q

What are the 4 different neurotrophins?

A
  1. nerve growth factor
  2. brain-derived neurotrophic factor
  3. Neurotrophin 3
    Neurotrophin 4/5
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8
Q

Describe each of the 7 steps.

A

1 = resting
2 = opening voltage gated Na+ gate in response to depolarizing stimulus –> brings the voltage to threshold potential
3 = positive feedback - membrane potential moves towards 60+mV
4 = doesn’t reach 60+mV during action potential, cause the increase in Na+ conductance is short-lived
- The Na+ channel remains in inactive state for a few milliseconds, before returning to a resting state when they can activated again
5 = Opening of the voltage gated K+ channels (slower to open than the Na+ channel) –> repolarization
6 = after-hyperpolarization, due to slow closing of the K+ channels
7 = return to resting potential

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9
Q

What are the different types of nerve fibers?

A
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10
Q

Describe spinal cord anatomy.

A
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