Question

Choose the incorrect statement w.r.t. rigor mortis.

• A. After death, cellular membranes become leaky, so calcium ions leak out of the sarcoplasmic reticulum into sarcoplasm
• B. Increasing level of Ca${}^{+2}$ in sarcoplasm allows myosin heads to bind actin
• C. ATP synthesis ceases shortly after breathing stops, so cross-bridges cannot break
• D. Muscles remain in a state of rigidity forever after death

Answer 1

The correct option is D Muscles remain in a state of rigidity forever after death

Rigor mortis begins 3 – 4 hours after death and lasts about 24 hours because proteolytic enzymes from lysosomes digest the cross-bridges.