I was at the beach today thinking I’m basically just a slab of meat in the sun. How come I don’t rot? What prevents living things from decomposing and how does that change when we die?
In: Biology
When you die, you stop breathing and your heart stops pumping blood round the body. This prevents oxygen (needed to convert energy-containing nutrients into actual energy) and required nutrients from reaching cells. It also prevents waste products from those cells from being flushed to the places where they can be processed (the liver and kidneys). They build up near the cells. So the chemical balance in your body starts to change. In addition, without blood-flow and the means to regulate cell activity, the body temperature starts to change, usually cooling, but sometimes heating up.
These changing conditions then allow some of the bacteria already in the body to grow in ways that they could not previously. In addition, without blood flow, there is no immune response to suppress those bacteria. In particular, bacteria that live without oxygen (anaerobic bacteria) flourish – these bacteria often produce gases like methane and Hydrogen Sulphide.
In the gut there are many different types of bacteria. Since food transport (peristalsis) has stopped, they just go to work on the remaining food in the gut, and each other. Again, the changing conditions favour anaerobic bacteria, and this creates large amounts of gas in the alimentary tract, causing bloating. Eventually the bacteria start on the gut lining, and into the rest of the body.
If you can keep supplying oxygen and maintain heartbeat, you can keep a “dead” body viable for a few days, as in the case of brain-dead patients on life support.
If circulation is impaired on a part of someone who is alive, necrosis (dead and rotting tissue) can set in.
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