The ecosystem of the dead: how to live the body immediately after death
As creepy as it may sound, after death the body continues to live: chemical processes take place in it, it can make sounds and even move, special processes are triggered in it, of course, different from providing human life, but no less important from a biological point of view. Yes, this is life in the figurative sense of the word, but from the moment of cardiac arrest, the body is a whole evolving ecosystem, living according to its own laws.
The heart has stopped, the blood has stopped circulating through the body, and the oxygen involved in all vital processes is no longer available. At this point, almost immediately after death, the cells begin to experience oxygen starvation, the process of autolysis begins, in other words, self-digestion begins, which first starts in the enzyme-rich liver, and then in other organs. Cells and tissues under the action of their own hydrolytic enzymes begin to dissolve, structural molecules are destroyed. Autolysis in nature is triggered not only by death but also by other physiological processes. Metamorphosis (when a caterpillar turns into a butterfly, or a tadpole into a frog) is also accompanied by autolysis.
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Gradually, the body temperature decreases to atmospheric values (the body cools by about 0.8 degrees Celsius per hour), followed by rigor Mortis. All the same, oxygen is no longer involved in the formation of adenosine triphosphate (ATP), which is of great importance in the exchange of energy and substances in the body. ATP is no longer hydrolyzed with calcium and its ions move from the intercellular fluid to the striated muscles, which is why a persistent muscle contracture is formed, in other words, contraction.
In the first hours after death, the muscles become soft. Rigor Mortis usually develops from two to five hours after death and by the end of the first day covers the entire musculature. The muscles become dense, decrease in volume, lose elasticity. The joints are fixed in a state of immobility. The rigor of the muscles develops in a certain sequence: first the muscles of the head, then the neck, forelimbs, trunk, and hind limbs. Flexor muscles are more powerful than extensors, so the body does not fully bend the upper limbs in the elbow joints, the hands are half-compressed, and the lower limbs are also half-bent in the hip and knee joints. Rigor Mortis persists for up to two or three days and then disappears in the same sequence as it occurs. This is followed by enzymatic decomposition.
After death, the immune system stops working, and the bacteria and microbes that infested the body during life are no longer restrained and travel freely through the body. Most of the "inhabitants" are in the digestive system, from there their "Banquet" begins. At first, the bacteria slowly absorb the intestines, feeding on the chemical "compote" that flows from the cells, then switch to the surrounding tissues.
After about 20 hours, the bacteria reach the liver, and it takes them just over two days to spread throughout the body. From this moment, death begins at the molecular level: the body's tissues completely disintegrate, turning into gases and liquids. Gradually, the pressure of gases increases in the body, they begin to leave the body's openings. Sometimes the pressure is so high that the abdominal cavity bursts. At this point, the decomposing organism begins to interact with the environment, attracting the attention of external microbes, micro-organisms, insects and scavengers.
Thus, the ecosystem of the corpse ceases to be limited by its own body, and a long-term active chemical and food exchange begins, as a result of which only the bone tissue remains.