Sarcomere of skeletal muscleकंकाल पेशी का सार्कोमियर

NCERT Fig 17.2 (b) · interactive diagram

Parts and their functions

• Z line (Z रेखा) — Bisects the I band; thin filaments are attached to it; sarcomere = Z to Z.
• I band (isotropic) (I पट्ट (समदैशिक)) — Light band; only thin (actin) filaments; shortens during contraction.
• I band (I पट्ट) — Light band; only thin filaments.
• A band (anisotropic) (A पट्ट (विषमदैशिक)) — Dark band = length of the thick (myosin) filaments; keeps its length during contraction.
• A band (A पट्ट) — Dark band = length of myosin filaments.
• H zone (H क्षेत्र) — Central part of the A band not overlapped by thin filaments; narrows in contraction.
• M line (M रेखा) — Thin fibrous membrane holding the thick filaments together in the middle of the A band.
• Actin (thin filament) (एक्टिन (पतला तंतु)) — Two F-actins + tropomyosin + troponin.
• Myosin (thick filament) (मायोसिन (मोटा तंतु)) — Polymer of meromyosins; heads form cross bridges.
• Sarcomere (सार्कोमियर) — Functional unit of contraction — between two successive Z lines.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 17.2 (b). Report a mistake