skeletal muscle tissue disorders Flashcards
type 1 fibers are
slow twitch: dark, aerobic
type 2 fibers
fast twitch: white, anaerobic
3 types of myopathy and neuropathy
- neuropathic changes: motor units fewer and larger
- disuse atrophy: primarily type 2 fibers
- glucocorticoid atrophy: primarily type 2 fibers
will congential myopathy get worse? muscular dystrophy?
no it is a static deficit, yes: rarely congenital, dystrophiopathy MC reason
what happens in muscular dystrophy
myocyte degeneration outpaces repair
Duchenne vs. becker MD… more severe? explain
duchenne: dystrophic is absent: childhood onset
becker: variable severity: abnormal dystrophin: adolescence
where do dystrophinopathies typically occur? pseudohypertrophy?
pelvic girdle weakness, calf muscles
how to check for dystrophinopathies
there will be elevated levels of creatine kinase from muscle breakdown
death from dystrohpinopathies due to
respiratory insufficincy
3 types of inflammatory myopathies
- polymyositis
- dermatomyositis
- includion body myositis
which inflam myopathy is autoimmune where t cells attack endomysium, males 45-60
polymyositis
which inflam myopathy is autoimmune, skin and muscle inflam, mc inflam myopathy in kids?
dermatomyositis
what inflam myopathy is in the elderly?
inclusion body myositis: degenerative
what are the 3 toxic myopathies
- thyrotoxic myopathy
- ethanol myopathy
- drug myopathy
what is thyrotoxic myopathy
thyroxine overproduction, graves disease
what is ethanol myopathy
binge drinking, rhabdomyolysis -> renal failure
MC drug for drug myopathy
statins
what is schwannoma and schwannomatosis
schwannoma: PNS nerver sheath, benign: MC CN 8
schwannomatosis: multiple cns and cutaneous schwannomas (never involving CN 8)
what is a neurofibroma
benign nerve sheath tumor
neurofibromatosis type 1
pronounced neurofibromas (cutaneous)
neurofibramatosis type 2
bilater vestibular schwannomas, vision and hearing probs
what is malignant peripheral nerve sheath tumor
transformed neurofibroma, large
where do 1/2 of malignant p. nerve sheath tumor disease come from
neurofibromatosis 1
what is a traumatic neuroma
reactive lesion from trauma or surgery
