AIIMS2012ZoologyLocomotion and Movement
During muscular contraction, which of the following events occur? (i) H-zone disappears (ii) A band widens (iii) I band reduces in width (iv) Width of A band is unaffected (v) M line and Z line come closer.
Options
- A(i), (iii), (iv) and (v)
- B(i), (ii) and (v)
- C(ii), (iv) and (v)
- D(i), (ii) and (iii)
Correct answer
A. (i), (iii), (iv) and (v)
Step-by-step solution
Muscle contraction is brought about by sliding of the actin filaments over myosin filaments. When a muscle fibril contracts, its A band remains constant and I band shortens. H zone also disappears as the actin filaments of both sides in each sarcomere may overlap each other at M line.