Rigor mortis in muscles
Process that causes the muscles in the body to stiffen resulting in rigidity due to a range of chemical changes in the muscle structure.
Rigor mortis starts in the 2nd hour and is completed in 3 hrs after death. Rigor mortis disappears 24 – 36 hrs after death due to autolysis.
Deficiency of ATP causing establishment of permanent link between actin and myosin. When ATP falls to 85% and creatine PO4 to 30% of its initial value, symptoms of rigor mortis begin to appear.
- Reasons of Rigors mortis-
- Ca++ pumps run out of ATP
- Ca++ cannot be removed
- Continuous contraction
- Eventually tissues break down
This is major physiological different between cardiac and skeletal muscles. Skeletal muscles ordinarily contracts only when stimulated by nerve impulse.
In contrast cardiac muscles tissue can contract with out our nerve stimulation. Its source of stimulation is conducting tissue of specialized muscle with in the heart.
Nerve stimulation causes the conducting tissue to increase or decrease its rate or discharge. Cardiac muscle tissue has got an extra long refractory period.
