Bio 140 Chpt 7 Skeletal muscle

What is a myofibril?

• a bundle of cells

• a group of tissues

• a segment of blood vessels

• a bundle of muscles fibers

Label A

• muscle fiber

• microfilament

• H zone

• Z disc

Label B

• microfilament

• myofibril

• sarcomere

• H zone

Label C

• H zone

• A band

• I band

• M zone

Label D

• sarcomere

• A band

• I band

• Z disc

Label F

• A band

• I band

• Sarcomere

• Muscle fiber

Label E

• A band

• I band

• Z disc

• H zone

Thick filaments are composed of a contractile protein called....

• actin

• myosin

• tropomyosin

• troponin

Thin filaments are composed of a contractile protein called ______.

• myosin

• tropomyosin

• troponin

• actin

A bands are.......

• light regions of the striations within a muscle fiber

• medium-colored regions of the striations within a muscle fiber

• dark regions of the striations within a muscle fiber

• A shaped lines within the muscle fiber