Quiz 4 Muscles Flashcards Preview

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Flashcards in Quiz 4 Muscles Deck (23):
1

Disuse atrophy

can be masked because increased fat develops between muscle fibers

2

neurogenic atrophy

loss of muscle mass as a result of damaged nerve supply

3

most common muscular dystrophy

Duchenne's

4

Duchenne's

due to defective gene on X chromosome that leads to inability to produce one of the proteins in skeletal muscle cell membrane (dystrophin)

5

What is the protein that is lacking in Duchenne's

dystrophin

6

hist of muscular dystrophy

tissue becomes disorganized, and concentration of dystrophin is decreased

7

early Duchenne's vs late

muscle fibers atrophy and fibrose due to excessive ca and increased reactive oxygen species. Fibrotic cells then degenerate and are replaced by fat

8

neuromuscular disease leading to fluctuating muscle weakness and fatigability

myasthenia gravis

9

myasthenia graves weakness is caused by what?

circulating antibodies that block acetylcholine receptors at post-synaptic neuromuscular junction and inhibit stimulative affect of acetylcholine

10

what muscles are affected in myasthenia gravis?

eye muscles, facial expression, chewing, talking, swallowing

11

what thymic abnormalities are related to males vs females with myasthenia gravis?

females: thymic hyperplasia
males: thymoma

12

hist of myasthenia gravis

large collections of lymphocytes and necrotic muscle fibers that appear pale and atrophic

13

progressive muscle weakness in upper arms and upper legs

Lambert-Eaton syndrome

14

Lambert-Eatons syndrome is associated with what?

small cell lung cancer

15

what receptors are affected in Lambert-Eaton syndrome?

ab to presynaptic ca channels in neuromuscular junction
- prevents normal function of calcium channels which inhibits release of acetylcholine

16

What are the three inflammatory myopathies?

dermatomyositis
polymyositis
inclusion body myositis

17

dermatomyositis

B and T cells
perifascicular muscle fiber atrophy
heliotrope purple rash around eyes and malar area
Gottron's sign

18

Gottron's sign

purple red papular rash over dorsal hands
associated with dermatomyositis

19

polymyositis

macrophage in muscles cells
no skin involvement
cytotoxic T8 lymphocytes in hist

20

inclusion body myositis

amyloid protein and inclusion bodies
inclusions in cells are pathonomonic

21

most common benign muscle tumor

rhabdomyoma
- usually on head or neck

22

most common malignant soft tissue tumor in children

rhabdomyosarcoma

23

hist of rhabdomyosarcoma

increased mitotic figures, darker staining nucleus