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-is unaffected
(v) M-line and Z-lne come closer
(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)

Answer

A

Explanation

Muscle contraction is brought about by sliding movement of actin filaments over myosin filaments. When a muscle fibril contracts, ita A band remain constant and I band shortens. H zone also disappears as the actin filaments of both sides in each sarcomere overlap each other at M-line. M-line and Z-line also come closer.