skeletal muscle tissue disorders

Question 1

type 1 fibers are

Answer 1

slow twitch: dark, aerobic

Question 2

type 2 fibers

Answer 2

fast twitch: white, anaerobic

Question 3

3 types of myopathy and neuropathy

Answer 3

1. neuropathic changes: motor units fewer and larger
2. disuse atrophy: primarily type 2 fibers
3. glucocorticoid atrophy: primarily type 2 fibers

Question 4

will congential myopathy get worse? muscular dystrophy?

Answer 4

no it is a static deficit, yes: rarely congenital, dystrophiopathy MC reason

Question 5

what happens in muscular dystrophy

Answer 5

myocyte degeneration outpaces repair

Question 6

Duchenne vs. becker MD… more severe? explain

Answer 6

duchenne: dystrophic is absent: childhood onset
becker: variable severity: abnormal dystrophin: adolescence

Question 7

where do dystrophinopathies typically occur? pseudohypertrophy?

Answer 7

pelvic girdle weakness, calf muscles

Question 8

how to check for dystrophinopathies

Answer 8

there will be elevated levels of creatine kinase from muscle breakdown

Question 9

death from dystrohpinopathies due to

Answer 9

respiratory insufficincy

Question 10

3 types of inflammatory myopathies

Answer 10

1. polymyositis
2. dermatomyositis
3. includion body myositis

Question 11

which inflam myopathy is autoimmune where t cells attack endomysium, males 45-60

Answer 11

polymyositis

Question 12

which inflam myopathy is autoimmune, skin and muscle inflam, mc inflam myopathy in kids?

Answer 12

dermatomyositis

Question 13

what inflam myopathy is in the elderly?

Answer 13

inclusion body myositis: degenerative

Question 14

what are the 3 toxic myopathies

Answer 14

1. thyrotoxic myopathy
2. ethanol myopathy
3. drug myopathy

Question 15

what is thyrotoxic myopathy

Answer 15

thyroxine overproduction, graves disease

Question 16

what is ethanol myopathy

Answer 16

binge drinking, rhabdomyolysis -> renal failure

Question 17

MC drug for drug myopathy

Answer 17

statins

Question 18

what is schwannoma and schwannomatosis

Answer 18

schwannoma: PNS nerver sheath, benign: MC CN 8
schwannomatosis: multiple cns and cutaneous schwannomas (never involving CN 8)

Question 19

what is a neurofibroma

Answer 19

benign nerve sheath tumor

Question 20

neurofibromatosis type 1

Answer 20

pronounced neurofibromas (cutaneous)

Question 21

neurofibramatosis type 2

Answer 21

bilater vestibular schwannomas, vision and hearing probs

Question 22

what is malignant peripheral nerve sheath tumor

Answer 22

transformed neurofibroma, large

Question 23

where do 1/2 of malignant p. nerve sheath tumor disease come from

Answer 23

neurofibromatosis 1

Question 24

what is a traumatic neuroma

Answer 24

reactive lesion from trauma or surgery