Question

Define rigor mortis.

Answer 1

Hint: The word rigor mortis is related to the stiffening of the body due to biochemical changes after death. Rigor mortis usually occurs between 2-6 hours after death. We have to define the term with proper explanation and description.

Complete answer:
It is defined as a change in the body after death or during postmortem time. It results in the stiffening of the body muscles due to some chemical changes in the myofibrils. It helps in the estimation of the time since death or the time when the person died. Rigor mortis is divided into three stages-
Absence - in this stage, the body still receives oxygen anaerobically.
Moderate- some more muscles start stiffening.
Advanced- almost all the muscles stiffen.
Complete- the whole body becomes hard.
Passed- the process of the rigor mortis ends.
The process of rigor mortis-
After the death of a person, the breathing stops which leads to the depletion of the oxygen source which is used in the preparation of ATP. ATP helps in the binding of actin- Myosin bridge which helps in the relaxation of the muscle and its absence leads to rigor mortis. When oxygen is no longer supplied, the body produces ATP through anaerobic glycolysis. After the amount of glycogen starts depleting, the ATP decreases and the body starts showing rigor mortis. The release of calcium into the cytosol is due to the deterioration of the sarcoplasmic reticulum. The calcium activates the formation of actin-myosin cross bridging. In rigor mortis, myosin heads start binding with active sites of the actin protein through ADP.
Rigor mortis is used to set standards in the food packaging and in medical fields.

Note: Rigor mortis has a great need in the recognition of the cause of death of a person, that is if the person died naturally or murder. It helps in finding the suspect. It helps in preserving the dead body of different animals for different purposes or humans for medical practicals.