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Rigor Mortis Mortis= death Rigor=stiffness. By Natalie Rochette. What is it?. One of the recognizable signs of death (mortis=death) chemical change in the muscles after death which cause the limbs of the corpse to become stiff and difficult to move.
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Rigor MortisMortis= deathRigor=stiffness By Natalie Rochette
What is it? • One of the recognizable signs of death (mortis=death) • chemical change in the muscles after death which cause the limbs of the corpse to become stiff and difficult to move. • Occurs due to the changes in the physiology of muscles when aerobic respiration ceases. (aerobic=with oxygen)
Causes • After a body has died, the chemical reaction producing these energy molecules is unable to proceed because of a lack of oxygen.
The cells no longer have the energy to pump calcium out of the cell and so the calcium concentration rises, forcing the muscles to remain in a contracted state. This state of muscle stiffening is known as rigor mortis and it remains until the muscle proteins start to decompose.
How long does it last? • It begins after around 3 hours, reaching maximum stiffness after 12 hours, and gradually ends approximately 72 hours after death. • It ends not because the muscles relax, but because autolysis takes over. • Autolysis- the self-digestion of the body's cells. • Decomposition then begins.
Stages • Delay phase -- while there is plenty of ATP in the muscle, the muscle will remain in the relaxed state and no cross bridges between the thick and thin myofilaments will occur.Onset phase -- As stores of ATP and Creatine Phosphate are used up, rigor bonds between the thick and thin myofilaments are formed. As more bonds are formed, the muscle loses extensibility.Completion -- When all of the CP is gone, the muscle has no way of regenerating ATP. Full rigor mortis will then set in.
Meat Industry (fun fact) • it partially determines the tenderness of meat. • If the meat is chilled then cold shortening occurs which shrinks the meat and due to this water is lost and that makes the meat hard.
Meat that is butchered and immediately frozen or eaten is usually tougher than meat that is butchered, and then "aged" in a cooler for a period of time due to the concept of rigor mortis. • To prevent cold shortening, a process known as electric stimulation is used and the carcass is stimulated with alternating current, causing it to contract and relax.
