Why do nails and hair continue to grow after death?

From a biological point of view, death can be defined as the extinction of the homeostatic process of a living organism. From a biological point of view, it also means the end of lifealthough nobody can prove if it also means the end of the conscience of the individual.

In the case of the human body, one of the primary signs of death is cardiac arrest and the decrease in body temperature. From here, the functions of the different organs stop and a process of decomposition begins and, as we have been told, the nails and hair will continue to grow for a certain time, sometimes you can even hear that for months or years.

Not all cells in the body die at the same time, that's true, but the events that are triggered after cardiac arrest do not give much room. The neurons of the central nervous system are the first to begin to die, between 3 and 7 minutes after cardiac arrest, since they do not have glucose reserves for longer and do not have mechanisms to metabolize other nutrients.

Some organs can be removed alive for perform transplants up to 30 minutes after death, for example the kidneys, liver or heart. And they can be implanted into the recipient in up to six hours.

Skin cells, where nails and hair are formed, stay alive a little longer. Until 12 hours after death can be extracted viable pieces of skin for grafting.

But nevertheless, it is quite unlikely that the nails and hair will continue to grow. There is not much interest in doing scientific studies on this, but with the starting biological conditions there is no reason for them to grow, and even if they did it does not seem that they would grow very much.

For nails to grow there must be active cell division. This is impossible without a continuous supply of oxygen and glucose. At the germinal base of the nail, under the lunula, layers of cells are formed that excrete the keratin matrix that forms the nail. The upper layers die leaving the keratin matrix, and the lower layers divide and push the upper layers. This causes the nail to grow at an average rate of approximately 0.1mm a dayspeed that decreases with age.

For hair to form, similar circumstances must occur. In the hair follicle, the cells divide and grow, forming hair with lower layers that push the upper layers. These cells divide very quickly, but this only happens if nutrients are burned for energy, a process that obviously requires the supply of these nutrients and the supply of oxygen to burn them.

It doesn't seem like nails and hair can grow long after death. Why does this myth persist? The explanation is very simple: the skin around the hair and nails retracts with dehydration, retracts towards the skeleton and makes them seem longerbut not because they have grown.

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