MS Flashcards
what are the 4 demyelination mechanisms
- oligodentrocyte or schwann cell death
- interference with myelin synthesis
- interference with myelin replacement
- myelin destruction immune mediated
what is the composition of myelin?
70% lipids
30% proteins (myelin basic protein, myelin associated glycoprotein, oligodendrocyte glycoprotein)
what two things contain myelin?
schwann cells (PNS) oligodendrocytes (CNS)
both from neural crest
shwann cells and oligodendrocytes are components of what systems
schwann cells (PNS) oligodendrocytes (CNS)
how much does each schwann cell myelinate the axon?
1mm
how many axonal segments do oligodendrocytes myelinate
each oligo. myelinates 60 axonal segments
conduction velocity of an axon is proportional to its _________ and the ditance between________
diameter
distance between ranviers nodes
what is the speed of an action potential
120 m/s
perivascular and perivenulat immune infiltration/ plaques in white matter
demyelination
most common immune mediated inflammatory demyelinating disease of the CNS
MS
MS
age group affected
sex affected
most common neurologic disease among young adults
incidence is highest from ages 20-40 but can start in childhood or after 50
female to male 7:3 (2.3:1)
prevelance for MS decreases with?
proximity to equator
Genetic risk for MS for
general population?
one parent or 1st degree relative affected?
both parents?
0.1%
4%
20%
MS is associated with major __________
histocompatibility complex II (MHC II) and certain DR2 haplotypes
most frequent cause of permanent disability in young adults aside from trauma (among CNS disorders)
MS
mean age of ms
28-31
what is the best theory explaining the demyelination in MS
begins as an inflammatory immune mediated disorder characterized by autoreactive lymphocytes –> later the disease is dominated by microglial activation and chronic neurodegeneration
immunopath of ms/ inflammation in conjunction with BBB disruption –> inflammatory T cells, B cells, and macrophages are typically seen–> presence of IgG and IgM oligoclonal bands in ___________ but not in the ___________
Cerebrospinal fluid
serum
immunopath of ms/ myelin reactive ______ are found in MS _______ and in the ______ and the peripheral circulation of patients with MS
T cells
MS plaques
CSF
no direct proof that an autoimmune causes MS as ……
no specific autoantibodies or autorecessive T cells directed against self antigen in the CNS can passively transfer MS to experimental animals
how does MS appear or look like
multiple discrete pink or gray areas that have a hard or rubbery texture are id’d within the white matter of the brain and spinal cord
in MS lesions can occur at any site within the CNS, they have a predilection for involvement of the _______, _______, ______, and______
juxtacortical and periventricular white matter the corpus callosum optic nerves and the dorsal spinal cord brain stem cerebellum
the characteristic neuropathologic feature of MS is the presence of focal ____________ within the CNS accompanied by variable degrees of _______ and ______ with partial preservation of axons
focal demyelinated plaques
degrees of inflammation and gliosis
On MRI we can see that MS can cause diffuse damage of _____________ both of which are associated with a progressive loss of _______
normal appearing white matter (NAWM)
normal appearing gray matter (NAGM)
Loss of brain volume
