The period shortly after death seems to be a strange thing. During this time, the body has undergone various changes, from being alive to being completely dead. Although some of these changes (such as hardening and discoloration) can be seen in crime TV shows, other changes seem far-fetched for the human body.
Nonetheless, what the corpse can do is shocking and creepy. From the birth of the awareness of death, the changes in the body after death are almost unrealistic and impossible to achieve. The following list is not suitable for the faint-hearted or those with stomach problems.
After death, the body begins to decompose. It goes through a process in which it begins to digest itself—yes, essentially feeding on itself to aid in decomposition—through a process called autolysis. We still know very little about human decay, but the growth of forensic research facilities, or “body farms,” together with the availability and ever-decreasing cost of techniques such as DNA sequencing, now enables researchers to study the process in ways that were not possible just a few years ago.
Soon after the heart stops beating, cells become deprived of oxygen, and their acidity increases as the toxic by-products of chemical reactions begin to accumulate inside them. Enzymes start to digest cell membranes and then leak out as the cells break down. This usually starts in the liver, which is enriched in enzymes, and in the brain, which has high water content; eventually, though, all other tissues and organs begin to break down in this way. Damaged blood cells spill out of broken vessels and, aided by gravity, settle in the capillaries and small veins, discoloring the skin.
This is when the bacteria in our bodies come into play. Our bodies host huge numbers of bacteria, with by far, most residing in the gut, which is home to trillions of bacteria of hundreds or perhaps thousands of different species. Most internal organs are devoid of these microbes when we are alive. Soon after death, however, the immune system stops working, leaving them to spread throughout the body freely. This usually begins in the gut, at the junction between the small and large intestines. Left unchecked, our gut bacteria begin to digest the intestines and then the surrounding tissues from the inside out, using the chemical cocktail that leaks out of damaged cells as a food source.