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Flashcards in Skeletal Muscle Deck (73):
1

myopathy

disorder of muscle

2

segmental muscle necrosis

destruction of a portion of the myocyte length

3

how does muscle regeneration occur

satellite cells reconstitute destroyed muscles

4

when does fiber hypertrophy occur

response to an increase in load

5

myotonia

tonic spasm of one or more muscles

6

hypotonia

deficient tone or tension

7

arthrogryposis

fixation joints in an extended or flexed position

8

what is creatine phosphokinase (CK; CPK)

enzyme highly concentrated in muscle and brain

9

Gower's sign

indicates weakness of the proximal muscles
- uses hands and arms to walk up form squatting position

10

Myofibril

repeating units of sarcomeres

11

What defines a sarcomere

Z line to Z line

12

what makes a thin filaments in the muscle

actin

13

what makes up thick filaments in the muscle

myosin

14

what is the Z band primarily made up of

actin

15

what is the cell membrane of a muscle cell called

sarcolemma

16

what is the cytoplasm of a muscle cell called

sarcoplasm

17

when a muscle cell contracts what regions contract, lengthen.

I band shortens
A band unchanged

18

acronym of muscle fibers

One slow fat red ox
1, lipid rich, high myoglobin, oxidative

19

which muscle fiber is for sustained use? sudden use?

fiber 1: sustained
fiber 2: sudden

20

grouped atrophy

loss of a motor neuron leads to atrophy of associated muscle

21

fiber type grouping

neuron/axon drop out leads to larger motor units

22

Denervation atrophy is disorder of what? breakdown of what?

- motor neurons
breakdown of myosin and actin

23

what is wrong in spinal muscular atrophy

progressive destruction of anterior horn cells and cranial nerve motor neurons

24

another name for spinal muscular atrophy

infantile motor neuron disease

25

how is spinal muscular atrophy inherited? what gene is messed up

autosomal recessive
-survival motor neuron 1

26

what happens to the cell in muscular dystrophy

internal nuclei
fibrofatty tissue

27

what protein is defected in Duchenne MD? what gene?

Dystrophin protein defect from abnormal gene at Xp21 ( deletion > frame shift or point mutation )

28

what are some clinical features of Duchenne MD?

normal at birth
delayed walking
pseudohypertrophy of calves
increase CK

29

how do Duchenne MD patients die

respiratory failure, cardiac decompensation, lung infection

30

compare Becker MD with Duchenne MD

Becker MD less common, less severe, later onset

31

what part of the body does Limb Gridle MD occur? what does this cause

proximal muscles
- waddling gait because of weak hip and leg muscles
-trouble getting out of chairs or climbing stairs
- reaching over head hard
- holding arms outstretched

32

Limb Gridle MD is a defect in what

dystrophyn glycoprotein complex

33

Facioscapulohumeral MD has weakness where in the body? clinical significance

-facial weakness
- wasting of upper arm and shoulder muscles
-scapular bones look like wings when the arms are raised

34

Emery-Dreifuss MD onset

10-20;

35

what is the clinical triad for Emery-Dreifuss MD

- early humeroperoneal weakness
-prominent contractures, ( elbows/ankles)
- cardiomyopathy

36

muscle clinical signifiance for myotonic dystrophy

stiffness, difficulty releasing grip
- precuss thenar eminence
- weak foot dorsiflexion
-weak intrinsic hand/wrist extension
-facial muscle atrophy and ptosis

37

what are other clinical findings for myotonic dystrophy

cataracts
endocrinopathy
cardiomyopathy

38

what is wrong in the autosomal dominant myotonic dystrophy? protein and gene?

Dystrophila myotonia-protein kinase (DMPK)
CTG repeat expansion on 19q

39

what is the anticipation of mytonic dystrophy

onset at a younger age in succeeding generations

40

what are three types of hypotonic channelopathies

hyp0kalemic
hyperkalmic
normokalemic

41

what is the most common hypotonic channelopathy, tell me about it

hypokalemic
- Ca channel mutation
-attacks of flacid weakness

42

MOA of malignant hyperpyrexia

release Ca from SR
- defective Ca channel and RyR1
-ATP depleted by muscle contraction
- anaerobic metabolism

43

treatment for malignant hyperpyrexia

Dantrolene

44

clinical presentation for malignant hyperpyrexia

hypermetabolic state with tachypnea and general muscle contraction

45

central core disease how is inherited

autosomal dominant

46

what is wrong in central core disease

RyR1 defect

47

central core disease is a risk for

malignant hyperthermia

48

what happens in Nemaline Myopathy

- non-progressive hypotonia, weakness
- proximal limb muslces
- subsarcolemmal spindle-shaped particles fromZ band material

49

what happens to nuclues of centonuclear myopathy

central nuclei usually confined to type 1 fibers

50

lipid myopathies

accumulate lipid in myocytes
- defects in carnitine transport system
- defect in mitochondrial dehydrogenase enzyme system

51

mitochondrial myopathies

-defective mtDNA or nuclear DNA
-ragged red fibers from aggregated mitochondira
- parking lot for paracrystalline inlcusions

52

Dermatomyositis

skin rash precedes or begins with myositis ( grotten lesions and discoloration of eyelids with periobritl edema)
- muscle weakness

53

Juvenline Dermatomyositis, how is it different from adult

GI involved causing abdominal pain

54

MOA of dermatomyositis

CD 4 t and b cells
- microvasculature attached by antibodies and compliment creating ischemia

55

Polymyositis

muscle weakness
- autoantibodies against tRNA synthetases
-cytotoxic CD8 t cells in endomysium destroy muscle

56

what lymphs are involved for DM, PM , IBM

DM: CD4 and B
PM: CD 8 T
IBM: CD8 T

57

which inflammatory myopathies respond to immunosupr

DM and PM

58

site of injury for inflammatory myopathies

DM: capillaries
PM: endomysium myocyte
IBM: endomysium myocyte

59

where do inflammatory myopathies begin on body

DM and PM: proximal
IBM: distal

60

intracellular deposits in inclusion body myosistis are similar to what other disease

Alzheimer's

61

what happens to the muslces of thyrotoxic mypopathy

acute or chronic proximal muscle weakness

62

clinicl symptom for thyrotoxic myopathy

exophthalmic ophthalmoplegia

63

clinical manifestations of hypothroidism myopathy

cramping/aching muscles
slow movements
slow reflexes
proximal weaknes

64

Ethonal myopathy, what happens after binge drinking

acute rhabdomyolysis

65

name 3 drugs for drug induced myopathies

steroid ( proximal weakness, type 2 fibers)
chloroquine ( proximal weakness)
statins

66

what is ICU myopathy related to ? what does this do to muscles

corticosteroid therapy
- degraded myosin thick filaments

67

MOA for mysthenia gravis

immunemediated loss of acetylcholine receptors

68

myasthena gravis patients present with

drooping eyelid
diplopia

69

what is the muscle response for myasthenia gravis

decremental decrease in muscle response to repeated sitmulus

70

what is the tenselon test

short acting anticholenesterase

71

Lambert-Eaton myasthenic sydnrome

antibodies inhibit presynaptic calcium channel and block aceylcholine release

72

Lambert-Eaton myasthenic syndrome most likely comes from what disease

small cell carcinoma in lung

73

what is the muscle response forLambert-Eaton myasthenic syndrome

enhanced neurotransmission with repeitive stimulation