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Flashcards in Pathology Deck (251)
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1

What surrounds the entire skeletal muscle?

epimysium

2

What surrounds the bundles of skeletal muscle fibres?

perimysium

3

What surrounds the individual muscle fibres?

endomysium

4

What are the 3 main indications for muscle biopsy?

-evidence of muscle disease (eg weakness, muscle symptoms, elevated CK)
-presence of neuropathy
-presence of vascular disorder (vasculitis)

5

what is fasciculation?

uncontrolled twitching of muscle

6

When CK level is higher than normal, in the 'low' classification, what type of disorder does this indicate?

neurogenic disorder

7

when CK level is higher than normal, in the 'intermediate' classification, what type of disorder does this indicate?

inflammatory myopathy

8

when CK level is higher than normal, in the 'high' classification, what type of disorder does this mean?

muscular dystrophy

9

what are the 5 main groups of myopathies?

-muscular dystrophies
-inflammatory myopathies
-congenital myopathies
-secondary myopathies
-metabolic myopathies

10

Why are ring fibres sometimes formed during muscle dystrophy?

condensation of the cytoplasm

11

Why can there be enlarged nuclei and increased number of nuclei during muscle dystrophy?

due to attempted regeneration co-existing with the atrophy

12

What type of inheritance is Duchenne's Muscular Dystrophy (DMD)?

x-linked

13

What muscles does Duchenne's Muscular Dystrophy (DMD) mainly affect?

muscles of the pelvic girdle

14

What type of inheritance is Becker's Muscular Dystrophy (BMD)?

x-linked

15

What muscles does Becker's Muscular Dystrophy (BMD) mainly affect?

muscles of the pelvic girdle

16

When is the onset of Duchenne's Muscular Dystrophy (DMD)?

2 - 4 years old

17

What is the life expectancy of someone with Duchenne's Muscular Dystrophy (DMD)?

20

18

What happens to the calves of patients with Duchenne's Muscular Dystrophy (DMD)?

pseudohypertrophy

19

What mutation causes Duchenne's Muscular Dystrophy (DMD)?

Mutations in dystrophin gene on long arm of chromosome X

20

What causes the different severities of Duchenne's Muscular Dystrophy (DMD)?

mutations resulting in frame shift- severe
mutations resulting in altered binding- moderate to severe
mutations in middle rod- mild (Beckers)

21

What does the mutation in the dystrophin gene in Duchenne's Muscular Dystrophy cause? (in terms of basement membrane and actin and Ca++ entry)

changes anchorage of actin cytoskeleton to basement membrane

uncontrolled Ca++ entry into cells

22

What does the change in anchorage of actin cytoskeleton to basement membrane in Duchenne's Muscular Dystrophy do to the muscle fibres?

makes them more liable to tear

23

What gene is mutated in Becker's Muscular Dystrophy (BMD)?

dystrophin
(variant of DMD)

24

compare disease progress of Beckers to Duchennes?

Beckers progression is much slower

25

What is myotonia?

inability to relax voluntary muscles after vigorous effort

26

What are inflammatory myopathies?

primary inflammation of muscle

27

What is polymyositis?

a chronic inflammatory myopathy
autoimmune

28

compare inflammatory myopathies to muscular dystrophies in terms of pain?

no pain in dystrophies, pain is present in inflammatory myopahties

29

What autoimmune proteins are found in polymyositis?

antibodies to muscle antigens

30

what type of lymphocytes are mainly involved in polymyositis?

cytotoxic lympocytes