Complete Solutions
Myelin =
- cellular structure w/unique lipid & protein composition
- insulates neurons & forms nodes
Action potentials travel rapidly:
from node to node (Nodes of Ranvier - the depolarized region of
the membrane)
What is node to node travel called?
Saltatory Neurotransmission (think sodium)
Myelin Sheaths _____ speed of AP down axon
Increase
Myelinated vs. Demyelinated - image
,MS =
- Multiple: affects numerous areas of the brain, optic nerves, &
spinal cord
- Sclerosis: characteristic plaques or sclerosed areas (hallmark)
- Disease of CNS - PNS not involved
Is there a cure for MS?
No - no known cause either
T/F: MS is the most common chronic disease affecting the CNS
in young adults
TRUE
Is MS more prevalent in men or women?
Women (2-3x more than men)
MS symptoms usually begin at what age?
20-40 y/o
,MS is more common in what geographical location?
- North of equator
- 2x as prevalent in northern states
Geographical location in mind, what Vitamin may play a role in
MS development?
Vitamin D
MS is more common among what race?
Caucasians
(lowest in Asians)
Viral etiology
- Direct attack on myelin and/or oligodendrocyte
- Produces antigens similar to human proteins (MBP) -
molecular mimicry
- Stimulation of autoimmune response --> demyelination
Genetic factors?
Likely, but no genes ID'd - likely multiple genes involved
- Monozygotic twins >>> Dizygotic (non-identical) twins
- higher incidence w/parent w/MS
Why some & not others?
- Some alleles of MHC may be better at displaying self-antigens
- genetic predisposition
, - environmental exposure
- migration studies suggest early life exposure
More favorable prognosis when:
- Age of onset: <40 y/o
- Gender: Female
- Initial symptom: optic neuritis or sensory symptoms (Less
favorable w/motor or cerebellar symptoms)
- Low attack frequency in early disease
- Lower # of lesions on MRI
- Relapsing/Remitting course of disease (vs. progressive)
MS is a:
- Generally progressive autoimmune-mediated inflammatory
disease of the CNS characterized by areas of demyelination in
the brain, optic nerve tracts, & spinal cord
- Lesions result in multiple & varied neuro symptoms
MS symptoms
- Sensory symptoms
- Weakness & clumsiness
- Visual disturbances
- Bowel & bladder dysfunction
- Stiffness & gait disturbances
- Mental & cognitive disturbances
MS Pathophysiology - Autoimmune theory