What happens to your body when you die?

As soon as the person dies, the human body starts to decay. This decomposition starts within 5 minutes of the death of the person. Slowly and gradually the human body turns into a skeleton and then into nothing. 

Some bodies tend to decay faster than others: the reason being the varying factors such as the weather, temperature, moisture, pH, and oxygen levels, cause of death, and body position.

Stage One: Autolysis

This is the first step of decomposition where the self-digestion of the human body begins. As soon as the heart stops working and the blood circulation is halted, the oxygen supply to the body ends. This causes the excess carbon dioxide to acidify the body. The toxic environment of the body causes the membranes to release their enzymes and muscle to get stiff.
This causes the skin to get loose and small blisters to start to appear either on both internal or external organs.

Stage Two: Bloat

As the membranes start to release the enzymes, gases are produced inside the body. The production of sulfur and sulfur-containing enzymes causes the skin to change its color. The gas production can cause the size of the body to enhance. The insects can also become active in the body.

The bacterial activity would cause the body to give out an unpleasant smell which is known as putrefaction. The reason why the places such as crime scenes where the murder took place smell so bad is bacterial activity on the body. The place where the murder has taken place and the body remained there for days tends to give a smell even after washing it properly.

Stage Three: active decay

The active fluids of the body start to release in the third stage of decomposition. This stage tends to turn the body into a liquid: the muscles, organs, and skin start to change their state and turn into liquid. What is left after this stage is only hair, cartilage, bones, and the byproducts of decomposition.

Stage Four: Skeletonization Decay

A body can reach this stage either within three weeks or after years. This depends upon the conditions where the body is kept or buried. By the end of the fourth stage, what is left of the human body is disarticulated bones.