Human decomposition is one of the most grotesque aspects of the cycle of life, but to me, it is also one of the most interesting. How does the body go from what we all look like, to a pile of bones, with no tissue, or fluids left behind? In the end, the whole decomposition process allows the recycling of energy flow and nutrient into the surrounding ecosystem. I did my steam project on the beautiful ugliness of the 5 stages of decomposition.
There are normally five stages of decomposition process, which are fresh, bloated, active decay, advanced decay and skeletal stage but sometimes bloated stage and active decay are incorporated into one as early decay stage(Hau, Hamzah, Lian, & Hamzah, 2014) Human decomposition begins approximately 4 minutes after death has occurred. The onset is governed by a process called autolysis – or self-digestion. As cells of the body are deprived of oxygen, carbon dioxide in the blood increases, pH decreases and wastes accumulate which poison the cells. Enzymes begin to dissolve the cells from the inside out, eventually causing them to rupture, and releasing nutrient-rich fluids. (Vass, 2001)
Stage one, considered the fresh stage, is where there is not much change seen to the naked eye. The corpse cools down to the ambient temperature, which is called algor mortis, and then moves into rigor mortis, which we just learned about in depth in class, where when oxygen is no longer present, the body may continue to produce ATP via anaerobic glycolysis. When the body’s glycogen is depleted, the ATP concentration diminishes, and the body enters rigor mortis because it is unable to break those bridges, and livor mortis, when the blood in the body starts pooling on the side that is closest to the ground.
Stage two is when you start seeing results of Bloating. The flesh becomes discolored and is a wet process. This process is called putrefaction. During putrefaction, bacteria undergo anaerobic respiration and produce gases as by-products such as hydrogen sulfide, methane, cadaverine, and putrescine. The buildup of resulting gas creates pressure, inflating the cadaver, and eventually forcing fluids out. (Hyde, Haarmann, Lynne, Bucheli, & Petrosino, 2013)
Stage three is called active decay. This is the most progressive and rapid of the stages. The skin is ruptured and creates open access to other animals and scavengers to feed. The ruptured skin may turn black, and the liquefaction of the soft tissues.
Black putrefaction, or late decaying stage is considered the fourth and advanced active decay. During advanced decay, most of the remains have discolored and often blackened. Putrefaction, in which tissues and cells break down and liquidize as the body decays, will be almost complete.
The final stage, skeletonizing, or Skeletal stage, Dry remains or skeletal stage is reached when there is a very high degree of bone exposure but extreme breakdown of the bone material has not started. During this stage, there will be small amounts of dried skin, tendon and cartilage will exist. The process of decomposition is significantly slowed to years, or decades. (Hau, Hamzah, Lian, & Hamzah, 2014)
In my makeup process, I tried other body parts, but the hand seems to be the best to demonstrate each stage, especially since there are 5 stages and 5 fingers to segregate properly the stages. The stages of decomposition are widely researched, and there is much more in depth explanations about the processes, the incest infestation and environmental factors. But hopefully this helps in a small understanding of the process we all go through at one stage or another.
Hau, T., Hamzah, N., Lian, H., & Hamzah, S. (2014). Decomposition process and post mortem changes. Sains Malaysiana, 43(12), 1842-1882.
Hyde, E., Haarmann, D., Lynne, A., Bucheli, S., & Petrosino, J. (2013). The living dead: bacterial community structure of a cadaver at the onset and the end of the bloat stage of decomposition. PLoS one, 8(10). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3813760/
Ioan, B. G., Manea, C., Hanganu, B., Statescu, L., Solovastru, L. G., & Manoilescu, I. (n.d.). The chemistry decomposition in human corpses.
Vass, A. A. (2001, November). Beyond the grave-understanding human decomposition. Microbiology Today.