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25 Cards in this Set
- Front
- Back
Describe Type I muscles fibers
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Slow-twitch (red) fibers
rich in Mitochondria & Oxidative enzymes |
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Describe Type II muscle fibers
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Fast-twitch (white) fibers
Poor in Mitochondria |
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What determines the type of fiber a myocyte contains?
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Motor neuron
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Define Neurogenic Atrophy
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disease of the Anterior Horn cell or its axon
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Describe the pathology seen in Neurogenic Atrophy
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Initial: individual atrophic angular fibers
Later: Groups of atrophic angular fibers |
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Neurogenic Atrophy
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What is seen here?
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What helps in diagnosis Neurogenic Atrophy?
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Fiber typing = after reinnervation, a cluster of Type I fibers are adjacent to a cluster of Type II fibers
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Fiber-typing used to diagnose Neurogenic Atrophy
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What is seen here?
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What diseases can cause Neurogenic Atrophy?
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1. ALS
2. Vasculitis 3. Trauma 4. Nerve compression (spinal cord disease) |
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List 3 Inflammatory Myopathies
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1. Dermatomyositis
2. Polymyositis 3. Inclusion Body Myositis |
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Dermatomyositis
-perifascicular pattern of injury |
What is seen here?
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What is the clinical presentation of Dermatomyositis?
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Rash + weakness + muscle pain
*has an association with Cancer (Lung CA) |
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What is the immune target of Dermatomyositis? What is it mediated by?
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Capillaries
Antibodies + Complement |
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Polymyositis = lack of skin involvement
-Endomysial process -inflammation tends to occur within the meat of muscle -nuclei are also sometimes not at the periphery |
What is seen here?
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Inclusion Body Myositis
-rimmed vacuoles that may contain Beta-amyloid & tau within |
What is seen here?
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Describe the clinical features of Inclusion Body Myositis
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1. occurs in Distal muscles first
2. Older subjects 3. Resistant to therapy = not responsive to steroids 4. Rimmed vacuoles |
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pathology of Dystrophies
-fiber size variation -increased central nuclei -degeneration, necrosis -regeneration -fibrosis |
What is seen here?
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Describe the pathology of Dystrophy
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1. Fiber size variation
2. increased central nuclei 3. degeneration, necrosis 4. regeneration 5. fibrosis |
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Dystrophy characterized by X-linked inheritance with a mutation in the dystrophin gene
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Duchenne & Becker Muscular Dystophy
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Central Core Disease (congenital myopathy)
-central pallor -disorganized sarcomeres with deficiency of ATPase |
What is seen here?
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Nemaline Myopathy (congenital myopathy)
-Rod-like inclusions derived from the Z-disc |
What is seen here?
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Myotubular (Centronuclear) Myopathy
-desmin, loss of myofibrillar material (EM) |
What is seen here?
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Mitochondrial Myopathy
-aggregates of abnormal mitochondria -Ragged red fibers -Cytochrome oxidase negative fibers |
What is seen here?
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-aggregates of abnormal mitochondria
-Ragged red fibers -Cytochrome Oxidase negative fibers |
Mitochondrial Myopathy
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Mitochondrial Myopathy
Proximal weakness -other neurological symptoms -lactic acidosis -Cardiomyopathy |
What disease is this? What does it cause?
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