ch 21 Flashcards
what cell in the PNS is responsible for myelin in the PNS
Schwann cells
what are the 3 parts to the motor unit of the neuron
- peripheral axon
- neuromuscular junction
- innervated myocytes
what is an Axonal neuropathy
this is caused by direct injury to an axon
what is the effect of an axonal neuropathhy
it will cause degeneration of the peripheral segment of the neuron
what is wallerian degeneration
this is a second degree myelin loss due to axonal neuropathy
what is demyelinating neuropathy
this is schwann cells or myelin cells damage this will cause random internod demyelination
what will happen to the nerve velocity if you have demyelinating neuropathy
this will slow the speed of how fast the signal is able to travel
what is mononeurpathy
this is an isolated neural damage due to some kind of entrapment like carpal tunnel syndrome
what is polyneuropathy
this is from a systemic axonal loss. this will cause a stocking-and-glove pattern, that is a loss of felling in the extremities
what is polyneuritis multiplex
this is just random demylinating
what are the 2 classic examples of polyneuritis multiplex
RA
wrist drop
what are the major symptoms of gulilain-barre syndrome(GBS)
this has ascending paralysis
autoimmune
demyrelination due to macrophages
who is most likely to get Guillain-Barré syndrome
males are 15-35 or 50-57
what is chronic inflammatory demyelinating polyneuropathy (CIDP)
this is thought to be the chronic version of Guillain-Barré syndrome
will most likely have relapse and progressive
what is the #1 cause of peripheral neuropathy
Diabetic peripheral neuopathy
what does diabetic peripheral neuropathy cause
it damages both the axon and myelin injury
what is the standard test for diabetic peripheral neuropathy
it is the monofilament test
what are some of the environmental toxins that will cause peripheral nerve injury
ADRs, lead, methyl-mercury
what is charcot-marie-tooth disease
this is an inherited peripheral nerve injury
this will cause pes cavus
what causes myathenia gravis
autoantibodies degrade the post-synaptic ACH receptors
what is the major symptom of myasthenia gravis
extra-ocular weakness (dropping eye)
who is most commonly effected by myasthenia gravis
females in the 3rd decade of life
what is the test that is used to diagnose myasthenia gravis
tensilon test
what will cause myasthenia gravis to get worse
worsens as day progresses or
worse with e-stimulation
what is the cause of lambert-eaton syndrome
autoantibodies inhibit pre-synaptic Ca+ channels
what is the most effect areas of the body with lambert-eaton syndrome (LES)
weakness in the limb girdles
what will help improve Lambert-Eaton syndrome
repetitive e-stimulation
who is most likely to get Lambert-Eaton syndrome
females in there 60s
also people with small cell lung cancer
what is congenital myasthenic syndromes
mutations alter neuromuscular junction proteins both per and post synaptic channels
are slow twitch muscles type I or type II
type I
are fast twitch muscles type I or type II
type II
what does neuropathic changes in muscles do
makes the motor units larger and fewer ( so they are bigger and also can change the type of muscle (Type I to II)
what does disuse atrophy do to muscles
this will cause atrophy to the muscle from lack of use mostly type II
what does glucocorticoid atrophy do to muscle
cause atrophy by preventing protein synthesis and speed up protein break down
primarily type II
what is congenital myopathy
it is inherited diseases
present at birth and does not get worse
does muscular dystrophy get worse the longer you live
yes
what is duchenne muscular dystrophy
it is the complete absence of dystrophin
what is Becker muscular dystrophy
it is not having enough dysrophin
when is the onset for Duchenne muscular dystrophy
in childhood around the age of 5
what is the outcome for Duchenne muscular dystrophy
it is lethal by early adulthood
what is the onset for Becker muscular dystrophy
delayed onset (adolescence)
what is the outcome for Becker muscular dystrophy
possible normal life span
what are the features of Dushenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD)
pronounced pelvic girdle weakness
pseudohypertrophy of the calf muscle (big calfs)
what will you find out in a lab test with DMD and BMD
increase in creatine kinase because of muscle breakdown
what does DMD and BMD do to the cardiorespiratory system
it decreases it causing it to have insufficiency
what is gower sign
it is the walking up of the hand to the legs and thigh because of pelvic weakness
who is most likely to get polymyositis
males ages 45-60
what is effected by dermatomyositis
both muscle and skin
who is the most likely to get dermatomyositis
it is the most common myopathy in children
who is the most likely to inclusion body myositis
the elderly 60+ because it is a age related muscle disorder
what will cause ethanol myopathy
binge drinking
what is most common to cause drug myopathy
statin drugs
who is most likely to get tumors in the PNS
adults
are PNS tumors most likely benign or malignant
benign
what is most likely to be effected by a schannoma
mc involves CN VIII (vestibular schwannoma)
what is a schwannomatosis
it involves the schwannoma but does not involve CN VII
what is a neurofibroma
it just a benign nerve sheath tumor
localized cutaneous, plexiform, or diffuse
what is neurofobromatosis type 2
it is bilateral vestibular scwannomas
no cutaneous lesions
what is the most common problem with neurofibromatosis type 2
vision and hearing problems
what does neurofibromatosis type 1 cause
very pronounced neurofibromas
causing vascular stenosis
look at the last page of ch 21 just in case he asks a questions
but i dont think he will because these are very unlikely
