Stages of death |
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1. Pallor mortis |
1. Pallor mortis
2. Algor mortis
3. Rigor mortis
4. Livor mortis
5. Putrefaction
6. Decomposition
7. Skeletonization
Putrefaction is the fifth stage of death, following pallor mortis, algor mortis, rigor mortis, and livor mortis. This process references the breaking down of a body of a human or animal post mortem (meaning after death). In broad terms, it can be viewed as the decomposition of proteins, and the eventual breakdown of the cohesiveness between tissues, and the liquefaction of most organs. This is caused by the decomposition of organic matter by bacterial or fungal digestion, which causes the release of gases that infiltrate the body's tissues, and leads to the deterioration of the tissues and organs. The approximate time it takes putrefaction to occur is dependent on various factors. Internal factors that affect the rate of putrefaction include the age at which death has occurred, the overall structure and condition of the body, the cause of death, and external injuries arising before or after death. External factors include environmental temperature, moisture and air exposure, clothing, burial factors, and light exposure.
The first signs of putrefaction are signified by a greenish discoloration on the outside the skin on the abdominal wall corresponding to where the large intestine begins, as well as under the surface of the liver.
Certain substances, such as carbolic acid, arsenic, strychnine, and zinc chloride, can be used to delay the process of putrefaction in various ways based on their chemical make up. At body farms, facilities which study the process of decomposition as well as how these substances affect the rate of putrefaction, cadavers are put in different environmental conditions to study how the process of decomposition can be affected. There are six University Body Farm Research Facilities in the world, all located within the United States, which include the University of Tennessee at Knoxville, Western Carolina University, Texas State University, Sam Houston State University, Southern Illinois University, and Colorado Mesa University. Two prospective body farms will open outside the United States, in Australia and India.