Death occurs when the body can no longer maintain its vital functions. This process often begins with organ failure, a gradual shutdown that can be prolonged in some cases, such as terminal illness. The heart stops beating, which cuts off blood flow to the brain, lungs, and other organs.
Without oxygen, the brain begins to die, and within minutes, brain cells are irreparably damaged. When the brain is deprived of oxygen, other organs and systems in the brain begin to die rapidly.
Once the body is clinically dead and resuscitation is no longer possible, the next stage is biological death. This marks the beginning of decomposition, a natural process that breaks down body tissues.
In the first stage of decomposition, known as autolysis, cells begin to break down due to the accumulation of carbon dioxide, which creates an acidic environment inside the cells. Enzymes that were once responsible for maintaining cell function now begin to digest cells from the inside out. This process usually begins within minutes to hours after death.
After autolysis, putrefaction begins. This is when bacteria that were previously controlled by the immune system begin to break down tissues, producing gases that cause the body to swell and emit strong odors. The body turns green because the bacteria break down the hemoglobin in the blood and release sulfur compounds.
Rigor mortis, or stiffening of the muscles, usually begins within two to six hours after death and peaks around 12 hours. This occurs because the body’s energy stores needed to keep the muscles relaxed are depleted.
After about 48 hours, the body’s muscles begin to relax again as the tissues further break down.
In the days and weeks following death, the body continues to decompose, eventually turning into a skeleton. This process is influenced by a variety of factors, including temperature, humidity, and the presence of insects or scavengers.
While clinical death, defined as the cessation of heartbeat and breathing, is instantaneous, the end of the brain and body is not.
