Nervous System Flashcards
Microglia
Active only after damage of neuron
Close to neuron
Flat cell bodies
Fibrous astrocytes are found in ______ matter
White matter
Near fibre - axon
Oligodendrocyte cell body shape
Pear
which neuron gets myelinated first sensory or motor
Sensory 4th to 5th month of foetal life
Motor 2 months after birth
According to Enanger gassier classification, which neurons are myelinated
A (4 types) & B type
Axoplasmic transport types
Anterograde via kinesin protein
Slow Fast
Retrograde via dyenin
Special features of neuronal mechanism
Conductivity , excitability &recovering phase occur in absence of O2
Energy req at resting polarised state is by sugar and phospholipids
Growth of nerve is influenced by
Neurotrophins (3,4,5,)
Brain derived neurotrophic factor(BDNF)
Wallerian degeneration is also called
anterograde degeneration (NOT of axon body and …)
1 Swelling and fragmentation of axis cylinder
2 myelin sheath degenerates to droplets
3 macrophages remove cell debris to leave neurilemmal sheath empty
4 cytoplasm grows into the neurilemmal sheath
SMMS (sytoplasm)
Retrograde regeneration
Site of injury To Axon hillock To Cell body
Nucleus displaced
Cell body swells to spherical and many organelles disappear
4 stages of nerve regeneration
1 multiple fibre formation
2 Entry of fibres into endometrial tube with help of distal Schwann cells
3 active growth of fibres
4 myelination
MEAM
Complications of nerve regeneration
1 Functional complications 2 complete atrophy 3 Neuroma 4 Denervation sensitivity 5 Phantom limb
Orthodromic
Antidromic
away from cell body to axon terminal
Towards the cell body
Unfatigueability of nerve fibres
Because action potential does not require energy
Myelopathy
Schwannoma , neurilemmoma, acoustic neuroma
Disease of myelin sheath
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