neurons Flashcards

1
Q

3 types of CNS cells

A
  1. ) neurons
  2. ) Glia
  3. ) Others
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2
Q

Features of neurons

A
  • Have dendrites/cell body/axon/axon terminals
  • Axon terminals communicate with other axons
  • Communicate electrically via synapses
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3
Q

Histology

A
  • Large neurons: speckly pattern: missel body

- H&E: stains nucleic acids blue and proteins red

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4
Q

What is LFB

A

LFB (luxol fast blue): stains myelin

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5
Q

What is CV

A

Stains Nissl (RER)

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6
Q

Types of neurons

A
  1. ) chemical

2. ) electrical

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7
Q

Features of electrical synapses

A
  • Have connexons and connecins
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8
Q

Features of chemical synapses

A
  • Rich in mitochondria

-

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9
Q

How does synaptic transmission take place?

A
  • Influx of calcium allows neurotransmitters to be released/fused on the membrane
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10
Q

Dendritic spines

A
  • Synapses are concentrated here
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11
Q

Synaptic plasticity

A
  • They are dynamic structures
  • Neural plasticity: basis of learning and memory
  • Spinal remodelling linked to neural activity
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12
Q

Features of neuronal heterogeneity

A

Heterogenous for::

  1. ) size
  2. ) morphology
  3. ) neurotransmitters
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13
Q

Features of upper motor neurons

A
  • Large
  • Excitatory
  • Glutamatergic
  • Long projection pyramidal cells
  • Use GABA
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14
Q

Oligodendrocyte features

A
  • Myelinating cells of CNS
  • Myelin insulates axons segments + enables rapid nerve conduction
  • Provides metabolic support for axons]- Myelin sheath segments interrupted for nodes of ranvier
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15
Q

Oligodendrocyte features

A
  • Myelinating cells of CNS
  • Myelin insulates axons segments + enables rapid nerve conduction
  • Provides metabolic support for axons]- Myelin sheath segments interrupted for nodes of ranvier]
  • can myelinate multiple axons
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16
Q

Myelin sheath features

A
  • Multiple layers of membrane
  • 70% lipid and 30% protein
  • Myelin specific proteins e.g. MBP involved in compaction
17
Q

Mircoglia features

A
  • Immune cells of CNS
  • Originate from yolk sac projenitors
  • In ‘rest’ they are highly ramified/motile processes (2-3 mm/min_
  • In activation: retract processes and become more rounded
  • proliferate at sites of injury (phagocytic)
18
Q

Functions of microglia

A
  1. ) Immune surveillance
  2. ) Phagocytosis
  3. ) Synaptic plasticity: pruning
19
Q

Astrocyte features

A
  • most numerous of the glial cells
  • Highly heterogenous
  • Common maker is GFAP
20
Q

Astrocyte morphologies

A

1.) Fibrous: white matter/contact blood vessels/pia/nodes od ranvier

21
Q

Astrocyte functions

A
  • developmental: radial glia
  • structure: define brain micro-architecture
  • envelope synapses: tripartite synapse
  • homeostatic: buffer K+
  • Metabolic support
22
Q

Specialised astrocytes

A

1.) rADIA

23
Q

Specialised astrocytes

A
  1. ) Radial glia: in brain development
  2. ) Bergmann glia (cerebellum)
  3. ) Muller cells (retina)
24
Q

MND spinal cord shows pathological changes in

A

Motor neurons/microglia/astrocytes

25
Q

What does pathological CNS lesions in MS involve

A

Oligodendrocytes/neurons/T lymphocytes

26
Q

What does acute symptoms in MS reflect dysfunction in

A

neurons

27
Q

CNS terminology

A
  • Abundance of neuronal cell bodies in nuclei
  • Axons gathered into tracts
  • Tracts that cross midline = commissures
  • Grey matter abundant in neural cell bodies & processes – neuropil contains few cell bodies
    White matter contains abundance of myelinated tracts & commissures
28
Q

PNS terminology

A

Cell bodies & supporting cells located in ganglia – e.g. dorsal root ganglia (DRGs)
Axons bundled into nerves
Many PNS axons are enveloped by Schwann cells (myelinating cellsof the PNS – neural crestderived)

29
Q

Blood brain barrier

A
  • blue dyes in blood won’t penetrate brain tissue
30
Q

How is the blood brain barrier formed?

A

Formed by endothelial cells/astrocytes and pericytes

31
Q

Features of the blood brain barrier

A
  • Endothelial tight junctions
  • Astrocyte end feet
  • Pericytes
  • Continuous basement membranes: lacks fenestrations
  • Need specific transporters for glucose/water
32
Q

What do circumventricular organs lack

A

Normal BBB: sensory and endocrine functions

33
Q

What are these circumventricular organs

A
  1. ) Subfornical organ
  2. ) Pineal body
  3. ) Area Postrema
  4. ) Posterior Pituitary
  5. ) Organum Vasculum of the Lamina terminalis
34
Q

CSF drainage

A
  • occurs via multiple roots

- perineural route via olfactory/brainstem/spinal nerves

35
Q

Features of ependymal cells

A
  • epithelial like
  • line ventricles + central canal of spinal cord
  • involved in CSF flow
  • Ciliated to facilitate flow
  • Allow solute exchange between vervous tissue and CSF
36
Q

Features of the choroid plexus

A
  • formed from modified ependymal cells: villi form around network of capillaries- large surface area
  • Main site CSF production by plasma filtration
  • GAP junctions between cells form blood-CSF barrier
  • Projections in ventricles