3. Neuronal cell biology Flashcards
What are the 4 points of the neuronal doctrine?
- The neuron is the structural and functional unit of the nervous system
- Neurons are individual cells not continuous to other neurons
- The neuronal has 3 parts; dendrites, soma and axon
- Conduction is from dendrites to some to end of axon
Function of dendrites
Increase SA and receive outputs
Function of axon
Carry information over long distances
Function of hillock
Action potential origin
Function of myelin
Coats axons, improves conductance
Node of Ranvier function
Break in myelin sheath
Allows saltatory conduction
Terminals function
output region
transmitter release
synapse with other neurones
In which direction is retrograde transport?
Terminals to axon to soma
In which direction is anterograde transport?
soma down axon to terminals
Speed of retrograde transport
5 mm per day
Speed of anterograde transport
rapid 300-400 mm per day
slow 5-10 mm per day
Oligodendrocyte function
form myelin sheath
Microglial cell function
scavengers
Astrocyte function
mop up neurotransmitters
What neurotransmitters can glia release?
ATP, glutamate
Which NS are oligodendrocytes responsible for myelin?
CNS - wrap over parts of 50 neurons
What causes myelin in the PNS?
Schwann cells wrap part of a single neuron
Major proteins in CNS myelin
PLP
Major proteins in PNS myelin
P0 and PMP22
What do mutations in PLP cause in mice, rats and humans
mice - jimpy, shaking pup, rump shaker
rats - md
humans - Pelizaeus-Merzbacher Disease
What do Th cells do in EAE?
Cause demyelination, chronic relapsing paralysis.
Why does EAE result?
Mutation in T cell receptor gene V beta 8.2
What can demyelination cause?
MS
CMT
Adrenoleukodystrophy
What does a defect in P0 and PMP22 cause?
CMT
How do the long chain fatty acids build up in ALD?
A deficiency in the peroxisomal enzyme catalyzing formation of lignoceroyl-CoA ligase
Defect in a peroxisomal membrane protein needed to import the ligase into the peroxisome
