White Lectures

• 100 billion (300 billion glia cells tho)
• Dendrites- graded changes in electrical pot, mag dep on size and xomplexity of aborization
• Axons- NOT graded; highway to and from body- Ms, MT-assoc. proteins, neurofilaments

• Fast anterograde- 200-400 mm/day; kinesin;
• -membrane proteins, lipids
• -NTs
• -SVs
• -mitochondria

• fast retrograde: 200-300 mm/day; dyenin
• -trophic factors
• -lysosomal vesicles, old membrane components

• Slow anterograde
• 1. SCa: 0.2-1 mm/day
• 2. SCb: 2-8 mm/day (rate of axonal growth also)

• -Cytoskeletal proteins (neurofilaments, MTs)
• -NZ of itnermediary metabolism

• Neuronal perikarya
• Dendrites
• Synapses

• Axons
• Astrocytes (adjacet to cell bodies)
• Oligodendroglia
• Microglia
• *glia not in PNS

• Axons
• Oligodendroglia (surrounding axons)

• Astorcytes
• Micoglia

• "nerve glue"
• supprotive cells
• "barrier systems"

• 1. Astrocytes
• 2. Oligodendroglia
• 3. Ependyma
• 4. Microglia

• "star-like" elaborate processes
• flimaentous proteins: glial fibrillary acid protein (GFAP), vimentin
• between bv's and neurosn= BBB
• isolate or insulate synapses and neuronal processes

• have foot processes that make connections
• 1. astrocyte to n's w/o synapses
• 2. astrocyte to n's w/ synapses
• 3. astrocyte to astrocyte
• 4. astrocyte to brain surface
• 5. astrocyte to capillary
• 6. astrocyte to axon (small axons don't have olig. but astrocyte instead)

• literally "fewer processes"
• lipid-rich myelin in olig membranes, enable saltatory conduction
• 2 config: gray= adj to cell bodies; white= surrounding axons (think perifasicular arrangement)
• 1 olig can wrap around many axons

• forms epithemlium that lines ventricular system of CNS
• barrier between brain and CSF
• simpliar to CSF-producing choroid plexus

• "scavenger cells"- remove debris at sites of injury or normal turnover (like macrohphages)
• only glial cell not neuroectoderm-derived, but mesenchymal

• A,O, & M NOT in PNS
• Schwann cell- principal supporting cell of PNS
• <1 um diam= unmy, still invested by Scell; 1 Scell can assoc with many unmyl axons
• >1 um diam= myl, myelin sheath, 1 Scell assoc with only 1 internode on a single axon

dendritic spines: increase SA; lacking in Down Syndrome->disruption in interneuronal communication

difuse axonal injury- traumatic ijury, can lead to motor peripheral neuropathies

• Astrocytes- "fibroblast of brain"; scar tissue= gliosis
• Oligo- "leukodystrophies"- loss of myelin from CNS
• Microglia- not "target" of disease, but lots seen when there's injury