Histo: Nervous Tissue Flashcards

1
Q

What are the two principal cell types of the nervous system?

A
  • neurons
  • neuroglia
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2
Q

CNS neurolglia

A
  • ependymal cells
  • oligodendrocytes
  • astrocytes
  • microglia
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3
Q

PNS neurolglia

A
  • satellite cells
  • schwann cells
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4
Q

3 functional classifications of neurons

A
  • sensory neuron: info coming at CNS
  • interneuron: helps process info coming in from multiple sources which affects motor neurons
  • motor neuron: info exiting CNS
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5
Q

3 parts of a neuron

A
  • Dendrites: collect electrical signals from other neurons
  • Cell body: makes proteins, integrates incoming signals and generates outgoing signals to axons
  • Axon: passes electrical signals to dendrites of another cell to cells of effector organs
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6
Q

Neuron parts

A

Green: dendrites
Gray: cell body
B: axon

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7
Q

How are structural classifications of a neurons determined?

A

They are named after the number of processes coming off of the cell body

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8
Q

Structural classifications of a neuron

A

Bipolar:
- 1 axon and 1 dendrite (2 processes, separated by cell body)
- found in sensory organs (ex: retina of eye)

Pseudo-unipolar:
- 2 axons: peripheral and central (1 process off of the cell body that branches immediately)
- peripheral axons have dendrites
- found in PNS

Multipolar:
- 1 axon and many dendrites (3+ processes)
- found in CNS

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9
Q

Another name for cell body?

A

Perikaryon

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10
Q

Cell body image

A
  • Light staining = euchromatin = active
  • Most organelles are located in cell body (lots of RER for protein production)
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11
Q

Cell body image nissl-stained

A

B arrows: nissl bodies
R arrows: golgi (shows up clear)

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12
Q

Dendrites:

A
  • Transmit information to the cell body
  • Contain the same organelles as the cell body EXCEPT GOLGI
  • Are supported by microtubules and intermediate neuro filaments (neurofibrils)
  • Unmyelinated
  • Branch
  • Larger in diameter than axons
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13
Q

Dendrite labeled on image

A
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14
Q

What are dendritic spines:

A
  • evaginations on dendrites that increase the SA of the cell membrane
  • synapses occur on the spines
  • can be added or taken off as needed
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15
Q

Dendritic spine image

A
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16
Q

Axons:

A
  • 1 axon per neuron
  • originates from axon hillock
  • has neurofibrils
  • usually myelinated
  • lacks nissl substance
  • action potentials originate at the initial segment (right at axon hillock)
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17
Q

Axon image

A

Looks clearish and off to the edge of cell body

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18
Q

Axon in EM
- locate axon hillock
- initial segment
- myelin

A
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19
Q

Image of chemical synapse

A
  • locate presynaptic neuron
  • locate postsynaptic neuron
  • locate synaptic cleft
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20
Q

Image of chemical synapse

A
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21
Q

Satellite cells (PNS neuroglia)

A
  • surround neuron cell bodies in ganglia
  • regulate O2, CO2, nutrients, and neurotransmitter levels around neurons in ganglia
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22
Q

Schwann cells (PNS neuroglia)

A
  • surrounds axons in PNS
  • responsible for myelination of peripheral axons
  • participate in repair process after injury
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23
Q

Oligodendrocytes (CNS neuroglia)

A
  • myelinate CNS axons
  • provide structural framework
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24
Q

Astrocytes (CNS neuroglia)

A
  • maintain blood-brain barrier
  • regulate ion, nutrient, and gas concentrations
  • absorb and recycle neurotransmitters
  • form scar tissue after injury
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25
Q

Microglia (CNS neuroglia)

A
  • remove cell debris, wastes, and pathogens by phagocytosis
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26
Q

Ependymal cells (CNS neuroglia)

A
  • line ventricles and central canal
  • assist in producing and monitoring CSF
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27
Q

Satellite cell and schwann cell on peripheral cell body

A
28
Q

Satellite cell image

A

darker nuclei = more heterochromatin = less active

29
Q

Schwann cell with myelin sheath

A
30
Q

T/F: schwann cells only myelinate a small segment of an axon

A

T

31
Q

Peripheral nerve image:

A
  • locate schwann cell
  • locate nerve fibers
32
Q

What are nodes of ranvier?

A
  • gaps formed between the myelin sheath where the axons are left uncovered
  • allow the generation of a fast electrical impulse along the axon
33
Q

Node of ranvier image:

A
34
Q

Node of ranvier EM:

A
35
Q

What are Schmidt-Lanterman Clefts?

A

small pockets of cytoplasm left behind during the Schwann cell myelination process

36
Q

What are the arrows pointing to?

A

Nodes of ranvier

37
Q

3 roles of astrocytes:

A
  • modulation of communication
  • nutrient transport from blood to neuron
  • supporting myelin coverage of neurons
38
Q

What 2 things do astrocytes come into contact with?

A
  • blood vessels
  • neurons
39
Q

Oligodendrocyte in white matter

A

“fried egg” appearance

40
Q

What is unique about oligodendrocytes?

A

They can myelinate multiple sections of an axon AND multiple axons

41
Q

Microglia

A
  • smallest of the CNS glia
  • can function as macrophages with their phagocytosis
  • release cytokines to modulate synaptic transmission
  • can cleave spines of dendrites
42
Q

oligodendrocyte in scanning EM

A
43
Q

Microglia with silver stain

A

Note spindly processing coming from cell body

44
Q

Microglia with H&E

A

Note rod-shaped nucleus

45
Q

Ependymal cells

A
  • can be squamous or columnar
  • can be ciliated (beat to circulate CSF)
  • line central cavities of brain and spinal column
46
Q

Ependymal cell image

A
47
Q

Ependymal cell image

A
48
Q

Autonomic (postganglionic) ganglia

A
  • multipolar cell bodies surrounded by satellite cells
  • located intramurally within certain organs
  • preganglionic nerves synapse here
49
Q

Sensory ganglia

A
  • unipolar cell bodies surrounded by cuboidal capsule cells
  • associated with cranial and spinal ganglia
  • no synapse
50
Q

sensory ganglia

A

circular neuron with central nucleus

51
Q

autonomic ganglia

A

nuclei on side of cell

52
Q

CT components layers of spinal nerve

A

epineurium
perineurium
endoneurium

53
Q

endoneurium and perineurim

A
54
Q

endoneurium perineurim and epineurium

A
55
Q

What is the cerebral cortex?

A

outermost layer of gray matter making up the superficial aspect of the cerebrum

56
Q

3 major parts of the brain?

A

cerebrum
cerebellum
brainstem

57
Q

3 layers of the cerebellum

A

molecular layer
purkinje cell layer
granule cell layer

58
Q

cerebellum image: identify 3 layers

A
59
Q

ID

A

multipolar neurons

60
Q

ID

A

multipolar neuron

61
Q

ID

A

dorsal root ganglion

62
Q

ID the small brown dots

A

satellite cells

63
Q

ID the pink dot

A
  • nissl substance
  • psedounipolar at axon hillock
64
Q

ID the type of neuron

A

multipolar

65
Q

Is there blood in the endoneurium?

A

NO

66
Q

Perineurium and epineurium labeled

A

endoneurium are brown and surrounding each little circle