14. Skeletal Muscle

Question 1

Skeletal vs cardiac vs smooth

Answer 1

Sk = Multinuclate at edge, striated, no branching
C = Central single nuclei, striated, branching
Am = Single central nuclei, not striated or branched

Question 2

Easier to see on which stain?

Answer 2

Striated = Iron haematoxylin
Sections = H&E stain

Question 3

Skeletal fibre structure

Answer 3

Myoblasts fuse to form multi-cell synctytium
Sarcomere -> myofibrils -> muscle fibres

Question 4

Describe sarcomere structure

Answer 4

Dark thick myosin
Light thin actin
Actin filaments anchored by accessory proteins
Tropomodulin stops actin developing

Question 5

Type of skeletal muscle

Answer 5

1 = Oxidative slow twitch, fatigue resistant and dark (ATPase rish)
2A = Both, fatigue resistant
2B = Glycolytic only, fatigues

Question 6

What senses stretch in muscles?

Answer 6

Muscle spindles composing of intrafusal muscles fibres wrapped around gamma afferent nerve fibres in a fibrocollagenous capsule

Question 7

Fibrocollagenous connective tissue between muscle fibres

Answer 7

Endomysium

Question 8

Fibrocollagenous connective tissue connect muscle fibres

Answer 8

Perimysium

Question 9

Fibrocollagenous connective tissue between muscle fascicles

Answer 9

Epimysium

Question 10

What connects muscle to bone?

Answer 10

Specialised Sharpey’s fibres = Bundles of collagen through Epimysium and periosteum of bone (wide SA)
Tendon = parallel collagen with fibroblasts (small SA)