myelin and myelnation Flashcards
What is the difference between oligodendrocytes and schwann cells?
oligrodendrocytes myelinate muliple axons or parts of axons in CNS.
Schwaan cells myelinate single axons in PNS. (surround all axons but may not myelinate)
What is myelin composed of?
water, dry lipid, protein
Why are there lines in myelin?
The protein-lipid-protein repeats
linked extrnal proteins - intraperiod line (faint)
linked internal proteins - major period line (dense)
What happens when cerebroside levels are low?
myelin forms but develops vacuoles. (can cause paralysis)
What is difference between PNS and CNS cerebrosides?
PNS has less cerebrosides and less sulfalide
CNS has more sphingomyelin
What are the CNS myelin proteins?
Myelin basic protein(MBP),
proteolipid protein (PLP),
Ig like molecules (mog and mag) and
enzymes (proteases, carbonic anhydrase)
What are the PNS myelin proteins?
P0 (PNS myelin protein) - Charcot marie tooth syndrome 1b
Myelin basic protein (MBP)
PmP-22 - CMT syndrome 1a
What age is multiple sclerosis onset?
20-40
What comes up on Mri in multiple sclerosis patient?
plaques (paraventricular white matter vunerable)
What type of disease is multiple sclerosis?
Primary myelination disease - axon sparing (no primary changes in axon)
What happens in multiple sclerosis?
Immune system attacks oligodendrocytes - macrophage and protease activity degrades myelin. Is an inflammatory response.
What treatments is there for multiple sclerosis?
steroids, immune suppressents, (antibodies +cyclophosphamide)
Vit D
What type of disease is guillian-barre syndrome?
Primary demyelination in periphery nerve.(schwaan cells) due to inflammatory response
When does guillian - barre syndrome usually develop?
after a viral or bacterial infection.
