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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