Miss X lifts weights. When she contracts her biceps muscle, all of the following pas of the muscle shoen EXCEPT the:
When Miss X contracts her biceps muscle the A bands do not shoen because they represent the length of the myosin filaments which is constant. The sarcomere is the distance between the Z lines/discs and shoens as the myosin-actin cross bridges are formed. I bands are areas that cross the Z disc and contain only the pa of the actin filaments that do not overlap with the myosin filaments. As the muscle shoens, overlap increases and the I bands shoen. This is the sliding filament mechanism of contraction. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 5. Excitable Tissue: Muscle. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds),Ganong's Review of Medical Physiology, 24e.
Sarcomeres
I bands
A bands
Inter Z line distance