Myofibril Structure Quiz

What are the dark discs that separate the segments of the myofibril called?

• A-bands

• Z-discs

• M-lines

• H-bands

What is the length of a sarcomere?

• 1-2 um

• 4-5 um

• 2-3 um

• 3-4 um

What type of filament is formed of myosin?

• Thin filaments

• Elastic filaments

• Thick filaments

• Intermediate filaments

What is the thickness of thick filaments?

• 10 nm

• 4 nm

• 15 nm

• 7 nm

What is the area in the center of the A-band that is not reached by thin filaments called?

• I-band

• M-line

• H-band

• Z-line

What connects the thick filaments together in a transverse direction?

• M-line

• I-band

• H-band

• Z-line

What is the composition of the Z-line primarily made of?

• Myosin

• Actin

• Actinin

• Titin

What is the function of titin in the sarcomere?

• Connects thick filaments

• Prevents too much stretch

• Forms the Z-line

• Creates the A-band

What surrounds each myofibril?

• M-lines

• Z-discs

• Transverse tubules

• Sarcoplasmic reticulum

What forms parallel tubules at the region of the A-band?

• Sarcoplasmic reticulum

• Transverse tubules

• Z-discs

• M-lines