neurons Flashcards
(36 cards)
1
Q
3 types of CNS cells
A
- ) neurons
- ) Glia
- ) Others
2
Q
Features of neurons
A
- Have dendrites/cell body/axon/axon terminals
- Axon terminals communicate with other axons
- Communicate electrically via synapses
3
Q
Histology
A
- Large neurons: speckly pattern: missel body
- H&E: stains nucleic acids blue and proteins red
4
Q
What is LFB
A
LFB (luxol fast blue): stains myelin
5
Q
What is CV
A
Stains Nissl (RER)
6
Q
Types of neurons
A
- ) chemical
2. ) electrical
7
Q
Features of electrical synapses
A
- Have connexons and connecins
8
Q
Features of chemical synapses
A
- Rich in mitochondria
-
9
Q
How does synaptic transmission take place?
A
- Influx of calcium allows neurotransmitters to be released/fused on the membrane
10
Q
Dendritic spines
A
- Synapses are concentrated here
11
Q
Synaptic plasticity
A
- They are dynamic structures
- Neural plasticity: basis of learning and memory
- Spinal remodelling linked to neural activity
12
Q
Features of neuronal heterogeneity
A
Heterogenous for::
- ) size
- ) morphology
- ) neurotransmitters
13
Q
Features of upper motor neurons
A
- Large
- Excitatory
- Glutamatergic
- Long projection pyramidal cells
- Use GABA
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
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
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
- ) Immune surveillance
- ) Phagocytosis
- ) 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
- ) Radial glia: in brain development
- ) Bergmann glia (cerebellum)
- ) Muller cells (retina)
24
Q
MND spinal cord shows pathological changes in
A
Motor neurons/microglia/astrocytes
25
What does pathological CNS lesions in MS involve
Oligodendrocytes/neurons/T lymphocytes
26
What does acute symptoms in MS reflect dysfunction in
neurons
27
CNS terminology
- 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
PNS terminology
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
Blood brain barrier
- blue dyes in blood won't penetrate brain tissue
30
How is the blood brain barrier formed?
Formed by endothelial cells/astrocytes and pericytes
31
Features of the blood brain barrier
- Endothelial tight junctions
- Astrocyte end feet
- Pericytes
- Continuous basement membranes: lacks fenestrations
- Need specific transporters for glucose/water
32
What do circumventricular organs lack
Normal BBB: sensory and endocrine functions
33
What are these circumventricular organs
1. ) Subfornical organ
2. ) Pineal body
2. ) Area Postrema
3. ) Posterior Pituitary
4. ) Organum Vasculum of the Lamina terminalis
34
CSF drainage
- occurs via multiple roots
| - perineural route via olfactory/brainstem/spinal nerves
35
Features of ependymal cells
- 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
Features of the choroid plexus
- 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
