MSK Basics

Question 1

What encloses a complete skeletal muscle

Answer 1

epimyseum

it is continuous with the tendon, binding it to the bone

Question 2

Perimysium

Answer 2

encloses each fascicle of muscle fibers

Question 3

Endomysium

Answer 3

encloses each individual muscle fiber

includes an external lamina produced by muscle fiber and ECM produced by fibroblasts

Question 4

Parallel bundles of muscle fibers

Answer 4

myofibrils

Question 5

what separates sarcomeres

Answer 5

Z lines

Question 6

thin filament component

Answer 6

actin

Question 7

Major protein of the Z disc

Answer 7

actin

Question 8

Thick filament component

Answer 8

myosin

Question 9

which protein spans the entire A band, is bound to proteins of the M line and to the Z disc?
how

Answer 9

myosin

with the help of titin

Question 10

how do you determine the distribution of muscle weakness in myopathies

Answer 10

neuro exam

Question 11

what labs do you complete dor Myopathy workup

Answer 11

MALE DERM 3CG

Muscle biopsy
ANA
LFTs
ESR
Anti-dsDNA
Extractable Nuclear Antigens
Rheumatoid Factor
Myositis profile
CRP
Compliment
CK
Genetics Testing

Question 12

Which stain enables visualization of general muscle structure

Answer 12

H&E

Question 13

Which stain visualized mitochondria, nemaline rods, and vacuoles

Answer 13

Gomori stain

Question 14

which muscle fibers stain darker?

Answer 14

Type 1

Question 15

What is the role of NADH in muscle staining

Answer 15

enables separation of fiber types based on the density of mitochondria
reveals mitochondrial distribution

Question 16

ATP4.3 vs ATP 9.6 in muscle staining

Answer 16

type 1 stains darker in 4.3

type 2 muscle fibers stain darker in 9.6

Question 17

What does PAS stain in muscles

Answer 17

glycogen

Question 18

myopathic injury

Answer 18

direct damage to myofibers

Question 19

segmental necrosis

Answer 19

destruction of a portion of the length of a myocyte

Question 20

Describe myopathic changes in regenerating fibers

Answer 20

rich in RNA= basophilic & blue

enlarged nuclei with prominent nucleoli that are often randomly distributed in the cytoplasm

Question 21

What happens when chronic disease states regeneration fails to keep pace with myopathic damage

Answer 21

endomysial fibrosis (collagen deposition)
dropout of myofibers
fatty replacement
Fiber hypertrophy
cytoplasmic inclusions in the form of vacuoles, aggregates of proteins or clustered organelles