Question

How does a human body die? When does death occur?

Answer 1

Hint: A human body is said to be alive when it responds to the environment, grows, reproduces, etc. However, a human body can be considered to be dead when it stops breathing.

Complete answer:
Just like a human is born, death is a natural consequence of life. A living human body has many complex mechanisms going on continuously like the generation of new cells and repair of damaged cells, different complex systems like circulation, digestion, respiration, and many more. But what happens when a human dies?
A few minutes after a human dies there are few changes that take place inside the body. The enzymes which help in the generation of energy now start acting on human body cells and killing them. This process is known as autolysis which is considered as the initial step of decomposition of a human body. This starts in the liver and brain first, then eventually all organs of the body are digested. The blood capillaries are broken down in autolysis which leads to the release of blood out of the cell that causes pale purple coloring of the skin.
With time the body runs out of oxygen, after two hours the muscles which require oxygen to function stiffens into place. These changes in small muscles start from eyelids, jaw, and neck is known as rigor mortis. This stiffening spreads to the entire body in about 12 to 20 hours after the death. The enzymes at this point digest gastrointestinal tract release gut bacteria which further starts eating the remaining tissues and organs producing gases like methane, hydrogen sulfide, and ammonia. These released gases built-up pressure within the abdomen inflating it. This pressure also forces the liquid to move out of the body through the nose, ears, and mouth. At this point, the body releases a sweet aroma that attracts insects like flesh flies. These insects lay eggs on the remaining body which serves as food for them leading to the whole decomposition of the human body.

Note:
The speed of decomposition of a body depends upon environmental temperature, the hotter the environment faster the enzymes digest the body. When a body stops receiving the oxygen it is still alive for a few minutes producing carbon dioxide which is acidic and it ruptures sacs inside the cells releasing the enzymes. The rotten and gross smell from a dead body is due to the sulfur gas released.