Lecture 3 Flashcards

1
Q

What is the Myelin Sheath formed by a Schwann cell?

A

Fat Layer (electrical insulation) that increases the speed of action potentials

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2
Q

What is the axon?

A

Transmits information away from the soma (similar to a wire)

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3
Q

What is the Node of Ranvier?

A

Exposed region of axons

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4
Q

What is the collateral axon?

A

Branch and plug into another cell (branching increases innervation to other cell)

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5
Q

What is the pre-synaptic terminal?

A

Enlargement of the end of the axons branches

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6
Q

What is a multipolar neuron?

A

Motor neurons

  • Many dendrites and an axon.
  • Dendrites receive approximately 10,000 inputs
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7
Q

What is a bipolar neuron?

A
  • Has a dendrite and an axon.
  • Retina, olfactory, epithelium.
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8
Q

What is a pseudo-unipolar neuron?

A

Appears to have an axon and no dendrites.

  • Somatosensory neuron
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9
Q

What is a Cortical pyramidal cell?

A

A motor neuron

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10
Q

What is the cerebellar purkinje cell?

A

Located in the cerebellum

a unique type of neuron-specific to the cerebellar cortex

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11
Q

What are sensory neurons?

A
  • Carries information from body periphery into the nervous system (gives rise to perception)
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12
Q

What is Afferent?

A

Information coming into the CNS

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13
Q

What are interneurons?

A

Most numerous, relay and local

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14
Q

What are relay (projection) interneurons?

A

Long axons, conveys signals over large distance (one part of brain to another)

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15
Q

What are local interneurons?

A

Short axons, connections with neurons

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16
Q

What are Glial cells?

A
  • Not neurons…neurons supporting cells.
  • 2-10x more numerous than neurons.
  • Do not have neuritis
  • Not electrically excitable
16
Q

What are motor neurons - efferent?

A

Information leaving the CNS.

17
Q

What are the types of Glial cells?

A
  • Astrocytes
  • Microglia
  • Oligodendrocytes
  • Schwann Cells
18
Q

What are Astrocytes?

A
  • Star-shaped cell bodies
19
Q

What are the Microglia?

A
  • Protective Function
20
Q

What are the Oligodendrocytes?

A
  • Forms myelin sheath in the CNS
21
Q

What are Schwann cells?

A
  • Forms myelin in the PNS
22
Q

What are the functions of Astrocytes?

A

1) Separates Neurons: insulates neurons and synapses

2) Regulates extracellular K+: highly permeable to K+ (potassium can move into it)

3) Improves signalling efficiency: absorbs neurotransmitter (chemical) from synaptic spaces.

4) Releases growth factors: refers to proteins that facilitate

23
Q

What are the functions of microglia?

A
  • Function with astrocytes to protect neurons from toxic substances.
  • Protect the CNS from foreign matter through phagocytosis
  • Bacteria, dead or injured cells engulfs contaminants
  • Protect the CNS from oxidative stress (free radicals)
24
Q

What are free radicals?

A

Doesn’t follow natural rules, only disrupts natural pathways.

An occasional oxygen doesn’t pick up a proton to make a protein, instead picks up electrons

25
Q

What do free radicals disrupt?

A
  • Cell Membrane
  • Proteins
  • DNA
26
Q

What are the effects of myelination?

A
  • Insulates the axon.
  • Prevents the length dependent decay of the action potential.
  • Increases efficiency/speed of action potential propagation.
27
Q

How does myelination speed up action potentials?

A
  • Induces Na+ channel (protein) clustering at nodes.
  • Improves axonal transport.. increase in neural filament.
  • Leads to larger diameter/Cross Sectional Area
28
Q

What is the speed of myelinated axon?

A

100m/s

29
Q

What is the speed of unmyelinated axon?

A

1m/s

30
Q

What type of axon would detect a fly?

A

The myelinated axon.

31
Q

What type of axon would it be if you did something that caused pain?

A

The unmyelinated axon.

  • Pain neurons are not active all the time (why they are unmyelinated)
32
Q

What are Oligodendrocytes?

A

Inside the central nervous system and behave similarly to Schwaan Cells by producing myelin

33
Q

How do they signal for myelination?

A
  • Release of ATP and adenosine from neuron
  • Stimulates Glial Cells to produce myelin.