Death is an inevitable part of life, and even though it may seem grim, it serves a purpose in making way for new birth. However, the presence of dead bodies can pose a risk of disease transmission. Thankfully, nature has its own way of tackling this issue.
Dr. Devin Pinauti, a criminal identification lecturer at Kent University, refers to this natural process as "the ecological decomposition system." It is a complex series of reactions that gradually breaks down a body until all that remains is a skeleton, a process known as skeletonization. But before reaching that stage, various tissues undergo specific transformations.
In an interview with IFLScience for CURIOUS Live, Dr. Pinauti delved into the intricacies of this process. He emphasized that death is not a momentary event, as commonly believed, but a lengthy and multifaceted process. "Decomposition begins shortly after death, and it is important to clarify that death is not an instantaneous occurrence," he explained.
According to Dr. Pinauti, death unfolds as a cascade of reactions and processes: first, a person loses consciousness, followed by respiratory suppression and a gradual decrease in heart rate until it stops completely. This stage is known as clinical death, during which revival is still possible through resuscitation efforts.
When the heart ceases pumping, the oxygen supply to cells diminishes, limiting their ability to produce adenosine triphosphate (ATP) – the cellular energy source. As cellular oxygen levels dwindle, anaerobic respiration kicks in as an alternative energy-generating mechanism, albeit a less efficient one. Unfortunately, this process leads to the production of lactic acid as a byproduct.
Consequently, the time frame for cell viability is limited, and the cessation of ATP production halts cellular transport mechanisms, rendering the cells unable to exchange with their surroundings. Cell conditions begin to deteriorate, leading to increased acidity. The acidic environment causes the dissolution of lysosomes within the cell, resulting in the release of enzymes and lysosomal contents, further damaging the cell.
Eventually, the cell disintegrates, a process known as necrosis or programmed cell death, which is irreversible. The released toxins and enzymes harm neighboring cells, initiating damage in tissues with the highest oxygen and water content, such as the brain, lungs, and stomach.
Brain death
The brain, being an energy-demanding organ, succumbs first, with brain cells starting to die after approximately four minutes of cardiac arrest. Once a significant number of brain cells perish, brain death occurs. While other parts of the body may continue to function for an extended period, the loss of neurological control leads to systemic failure.
From a chemical standpoint, death signifies the failure of our biological systems to restore chemical equilibrium. The subsequent stages involve a return to equilibrium while various biological agents act upon the body. With the immune system no longer functioning, bacteria that are crucial for gut health proliferate, consuming nutrients and spreading throughout the body via the bloodstream.
The metabolic activities of the bacteria contribute to decomposition, generating volatile organic compounds responsible for the distinct odor associated with death. These compounds, comprising around 400 to 500 that have been identified in humans, attract insects to the decaying body.
In summary, death is not a singular moment but a gradual and intricate process. The ecological decomposition system, through a series of reactions, transforms a body into a skeleton. Understanding these stages provides valuable insights into the natural journey of death.