Question

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

• A. i, iii, iv , v
• B. i, ii, v
• C. ii, iv, v
• D. i, ii, iii

Answer 1

The correct option is A

i, iii, iv , v

Muscle contraction is brought about by sliding movement of actin filaments over myosin filaments. When a muscle fibril contracts, it’s A band remains constant and I band shortens. H – Zone disappears. M – line and Z – line also come closer.