Term
define descending structure of muscles; |
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Definition
brachioradialis muscle: bundle of muscle fibers: muscle fiber with motor neuron: nuclei, mitochon of myofibrils: sacromeres: actin and myosin |
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Term
Key features of normal muscle |
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Definition
1. all nuclei at periphery 2. internal structure of fibers is regular 3. no appreciable connective tissue (collagen) btwn fibers "endomysium" |
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Term
STATE 3 different motor neuron types |
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Definition
Type 1 fibers; type 11A fibers; type IIB fibers |
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Term
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Definition
low twitch, require O2, sustained muscle control, rich in mitochondria |
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Term
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Definition
fast; glycolytic; rich in glycogen |
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Term
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Definition
fast glycolytic; oxidative |
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Term
Are motor neuron types segregated or integrated? |
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Definition
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Term
Name histopath changes of muscle finers in muscle diseases. READ |
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Definition
1. neurogenic atrophy 2. muscle fiber degen (necrosis) and regen 3. cytoarchitect changes and inclusions in MFs 4. atrophy 5. vasculitis 6. end-stage muscle with atrophy, fibrosis, and fatty replacement 7. Neoplasms |
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Term
How are muscle fibers reinnvervated? |
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Definition
damage 1 nerve, reiinveration by collateral sprouts from remaining axon which induces regrowth of muscle fibers and alteration in muscle fiber type, leading to fiber type grouping. |
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Term
what does reinnveration allow for? |
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Definition
It allos for the type of muscle fiber to be changed--which may lead to different function. This all leads to progressive loss of muscle function |
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Term
What is the hallmark of initial destructive myopathy? |
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Definition
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Term
Order: necrosis, basophilic regenerating fiber, macrophage invasion and regen of myoblasts; fusion of myoblasts. |
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Definition
necrosis, macrophage invasion and regen of myoblasts; fusion of myoblasts; basophilic regenerating fiber. |
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Term
what are inflammatory myopathies characterized by? |
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Definition
muscle fiber degen (necrosis) and regeneration AND inflammation (perivascular, perimysial, and endomysial) |
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Term
What distinguishes inflamm myopathies from other types of myopathies (such as muscular dystrophies)? |
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Definition
the presence of perivascular, perimysial, or endomysial inflammation along with the pattern of muscle fiber atrophy |
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Term
What are 3 major inflammatory myopathies? |
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Definition
1. polymyositis
2. dermatomyositis
3. inclusion body myositis |
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Term
Describe who gets polymyositis. |
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Definition
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Term
what muscles are affected in polymyositis? |
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Definition
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Term
are serum CK levels depressed in polymyositis? |
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Definition
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Term
what is the pathology of polymyositis? |
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Definition
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Term
in polymyositis, where is the inflammation directed? |
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Definition
at the muscle fibers, with active invasion by inflammatory cells. |
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Term
In polymyositis, where is the distribution of inflammation? |
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Definition
perivascular, endomysial, perimysial |
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Term
What age do you get dermatomyositis? |
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Definition
any age, but 2 peaks in childhood and in adults |
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Term
do male or females get dermatomyositis? |
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Definition
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Term
What is distinguishing feature of dermatomyositis? |
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Definition
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Term
What type of atrophy in dermatomyositis? |
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Definition
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Term
What is the pathogenesis of dermatomyositis? |
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Definition
B-cell AB mediated vascular disorder |
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Term
What types of rashes found in dermatomyositis? |
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Definition
1. rash on extensor surfaces on extremities, 2. Heliotrophic rash, 3. Gottron's nodules on knuckles |
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Term
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Definition
immunosuppresion (steroids), azathioprine, methotrexate. |
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Term
What is inflammed in dermatomyositis? |
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Definition
the capillaries, NOT the myofibers |
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Term
dermatomyositis is predom what type of disease? |
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Definition
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Term
Are myofibersl generally affected by dermatomyositis |
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Definition
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Term
What gets deposited around capillaries in dermatomyositis? |
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Definition
Compliment deposition (C5b-9) around capillaries |
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Term
Who gets Inclusion Body Myositis? |
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Definition
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Term
Which muscles are affected in Inclusion Body Myositis? |
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Definition
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Term
What are the distinguishing features of Inclusion Body Myositis? |
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Definition
you get inclusion bodies in muscle fibers that have rimmed vacuoles. |
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Term
What fills the rimmed vacuoles in Inclusion Body Myositis? |
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Definition
filamentous material or tubulovescular material |
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Term
What are 2 pathological finding of Inclusion Body Myositis? |
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Definition
1. endomysial inflammation 2. focal invasion of muscle fiber by inflammatory cells |
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Term
Who gets Duchenne muscular dystrophy? |
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Definition
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Term
What are the common features of Duchenne muscular dystrophy? |
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Definition
1. prox. progressive weakness 2. pseudohypertrophy 3. elevated CK levels. |
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Term
Is there a total absence of dystrophin in Becker's muscular Dystrophy? |
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Definition
No. Only in Duchenne muscular dystrophy. |
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Term
What are the 2 path hall mark features of Duchenne muscular dystrophy? |
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Definition
1. necrotic muscle fibers 2. phagocytosis (and invasion of fibers by macrophages) 3. Fibrosis -->pseudohypertrophy |
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