Skeletal muscle

Question 1

Major contractile proteins in skeletal muscle

Answer 1

actin and myosin

Question 2

Striation visible under electron/ light microscopy for myosin

Answer 2

A-bands: represent myosin filaments
H-Bands: Central myosin filament segment
M-lines: Connections between adjacent myosin filament in their central region

Question 3

Striation visible under electron/ light microscopy for actin

Answer 3

I-bands: Represent actin filament
Z-discs: Attachment between adjacent sarcomeres within fibril

Question 4

Type of muscle contraction

Answer 4

Isotonic: Muscle tension is constant, length changes
Isometric: Muscle tension is generated while length remains constant
Isokinetic: Muscle contracts maximally at constant velocity throughout range of movement

Question 5

Sliding filament contraction mechanism

Answer 5

Cross bridge theory: Filaments of myosin and actin move relative to each other because of an oscillating binding site on the myosin molecule, which binds to actin molecule at differing rates

Question 6

Muscle fibre types

Answer 6

Type 1: Slow oxidative fibres
Type 2a: Fast oxidative fibres
Type 2b: Fast glycolytic fibres