Death is a natural process in which the body's life-sustaining functions gradually stop working. When a person dies, their body goes through several phases, which we will introduce to you today.
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Cardiac arrest
Cardiac arrest is the process in which the heart stops beating and thus ceases the vital pumping function of the blood in the body. This is often the immediate precursor to death and marks the beginning of the end of all life-sustaining processes in the human organism. Cardiac arrest leads to an abrupt interruption of blood circulation, which means that vital organs and tissues are no longer supplied with oxygen and nutrients.
As soon as the heart stops functioning, the oxygen supply to the cells is interrupted. Cells need oxygen for aerobic respiration, a process that produces energy in the form of adenosine triphosphate (ATP). Without ATP, cells cannot maintain their vital functions, which leads to cell death. The brain, which reacts very sensitively to a lack of oxygen, is one of the first organs to be affected by this deficiency. Irreparable damage to the brain can occur just a few minutes after a cardiac arrest, as the neurons begin to die.
Cardiac arrest can be triggered by various causes, including heart attack (myocardial infarction), drowning, electric shock, severe trauma and certain diseases of the heart itself, such as cardiac arrhythmias. Regardless of the cause, restoring blood flow and thus oxygen supply to the organs through immediate medical action such as cardiopulmonary resuscitation (CPR) and defibrillation is crucial. These measures can increase the chances of surviving cardiac arrest and prevent serious long-term damage.
After death by cardiac arrest, various post-mortem processes begin in the body, as already described. These include rigor mortis, autolysis or self-digestion of the cells and finally putrefaction, in which microorganisms and bacteria break down the soft tissue until only the skeleton remains.
It is important to emphasize that time is a critical factor in cardiac arrest. Restoring blood flow quickly can be critical to ensuring survival and minimizing damage. Therefore, knowledge of first aid and in particular CPR is life-saving and plays a crucial role in the response to a cardiac arrest.
Cellular death
Cellular death is the process by which cells cease to function and lose their structural integrity, ultimately leading to loss of life. This can happen as part of the natural ageing process, through disease, or as a result of an acute injury or event such as cardiac arrest. Cellular death is a key aspect of understanding what happens in the body when we die and can be broken down into two main categories: Necrosis and apoptosis.
Apoptosis
Apoptosis is programmed cell death, a controlled process that is necessary for the development and maintenance of the health of organisms. During apoptosis, the cell shrinks, fragments its DNA and divides into smaller, membrane-enclosed particles that can be safely absorbed and degraded by surrounding cells. This prevents an inflammatory reaction that could otherwise occur when cell contents are released into the surrounding tissue. Apoptosis is crucial for embryonic development, immune defense and the removal of damaged or diseased cells.
Necrosis
In contrast, necrosis is a form of cellular death caused by external factors such as injury, infection, toxins or a lack of oxygen (hypoxia). In necrosis, the cell swells, its plasma membrane breaks down and the cell contents are released into the surrounding tissue. This often leads to an inflammatory reaction in the surrounding tissue as the body attempts to eliminate the dead cells and their contents. Necrosis can occur in large areas where a lack of blood flow leads to massive cell death in the heart muscle.
Consequences of cellular death
The death of cells has a direct impact on the function of the associated tissue and organ. Massive cell death, as occurs after cardiac arrest, leads to a loss of function in the affected organ. In the brain, for example, the loss of neurons can lead to irreversible damage and the loss of cognitive functions or motor skills. In the heart, the loss of muscle cells can impair the pumping function, leading to further health complications.
Cellular death and the human body after death
After the death of an individual has occurred, cellular death processes begin throughout the body. Autolysis, a process of self-digestion in which cellular enzymes break down cellular structures, begins. This is part of the first phase of decomposition, in which cells begin to digest themselves without the regulatory signals of the living body. The process of autolysis paves the way for later decomposition, which is driven by microbial activity.
Overall, cellular death plays a central role in the process of dying and the subsequent decomposition of the body. It is a natural and unavoidable part of the life cycle and contributes to the renewal and maintenance of the ecological balance.
Rigor mortis
Rigor mortis is a postmortem process that occurs after an individual has passed away. This process is characterized by the stiffening of the body's muscles and is one of the clearest signs that death has occurred.Rigor mortis is a temporary phenomenon causedby a series of biochemical processes at the cellular level and can provide significant insight into the time of death.
Onset of rigor mortis
Rigor mortis typically begins within 2 to 6 hours after death, first in the smaller muscles such as those of the eyelids and jaw, and then spreads to the larger muscles of the body. Rigor peaks within about 12 hours of death and can last for 24 to 48 hours before finally subsiding as the muscles begin to loosen due to advanced decomposition.
Biochemical causes
The main cause of rigor mortis is the change in the biochemistry of the muscles post-mortem. During life, the interaction between the molecules actin and myosin in the muscle cells enables muscle contraction and relaxation, a process driven by ATP (adenosine triphosphate). After death, the production of ATP ceases as the body can no longer use oxygen to generate energy through cellular respiration.
Without ATP, the myosin molecules that would normally detach from the actin filaments to allow muscle relaxation can no longer be released. This results in the muscle fibres remaining in a state of contraction, causing the body to stiffen. In addition, the breakdown of ATP contributes to an accumulation of lactic acid, which leads to a drop in the pH value in the muscle cells and further strengthens the bond between actin and myosin.
Meaning of rigor mortis
Rigor mortis is an important phenomenon for forensic investigations, as the onset, intensity and subsidence of rigor mortis can provide clues as to the time of death. However, various factors such as the ambient temperature, the age of the deceased, the physical condition before death and the cause of death can influence the process of rigor mortis.
Easing of rigor mortis
After rigor mortis has fully set in, it eventually begins to subside as the cellular structures of the muscles decompose due to the autolytic processes and the onset of putrefaction. This causes the rigid muscle connections to break and the body regains flexibility. The easing of rigor mortis marks the transition to later phases of decomposition, in which microbial activity and chemical processes continue to drive the decomposition of the body.
Overall, rigor mortis is a fascinating, if macabre, aspect of human death that offers profound insights into the processes that take place in our bodies after the end of life.
Effects on the organs
The death of an organism is a complex process that affects every organ and system in the body. The effects of death on individual organs can vary, depending on the specific circumstances of the death and the time that has passed since death occurred. Here is a more detailed look at what happens to the major organs and systems when a person dies.
The heart and circulatory system
- The heart
Death and its effects on the heart are closely linked to the process of cardiac arrest, which is defined as a sudden cessation of cardiac function. This event marks the beginning of the end of life and has profound effects on the heart and the entire organism.
The heart is often one of the first organs to stop functioning. Death occurs when the heart stops beating and pumping blood through the body. This leads to the cessation of oxygen and nutrient supply to all other organs.
Cardiac arrest and the onset of death
Cardiac arrest occurs when the heart stops beating and blood circulation is no longer guaranteed. As a result, the organs, including the brain, are no longer supplied with oxygen and nutrients, which ultimately leads to death. The heart itself is also affected by this interruption of the blood supply, as it relies on oxygen to function like any other organ.
Direct effects on the heart
As soon as death occurs and the blood flow stops, the cells of the heart muscle (myocardial cells) begin to change. Without the supply of oxygen and nutrients, the cells can no longer produce energy, which leads to a rapid loss of their ability to function. This lack of energy causes the ion pumps of the cell membranes to stop working, leading to an imbalance of electrolytes inside and outside the cells. The direct result of this imbalance is the loss of the heart's ability to generate and conduct electrical impulses, which are necessary for the coordination of heartbeats.
Cellular death in the heart muscle
After cardiac arrest, the process of autolysis begins, in which the cells decompose themselves due to the lack of oxygen supply. The enzymes that were previously active in the cell's metabolism begin to break down the cell structures. This leads to cellular death in the heart muscle, which ultimately impairs the integrity of the heart as an organ.
Long-term changes
As time progresses after death, the heart and other organs undergo further changes characterized by the breakdown of tissues and the action of decomposition processes. Microorganisms that are naturally present in the body begin to break down the tissue, leading to further decomposition of the heart. This process is influenced by environmental factors such as temperature and humidity.
Forensic significance
Examination of the heart after death can provide important forensic evidence, particularly in determining the cause of death. Pathological changes to the heart, such as blocked arteries or damage to the heart muscle, can indicate cardiovascular disease that may have led to death. The analysis of blood clots and the condition of the heart muscle can also provide information about the circumstances of death.
Overall, death shows its immediate and long-term effects on the heart through the cessation of cardiac function, the onset of cellular death and the subsequent decomposition of cardiac muscle tissue. These processes emphasize the central role of the heart in the living organism and the profound changes that accompany the onset of death.
- Circulatory system
Death and its effects on the circulatory system are fundamentals of the transition from life to death. The circulatory system, consisting of the heart, blood vessels and blood, is responsible for the distribution of oxygen, nutrients and other vital substances throughout the body. Once death occurs, this system ceases to function, resulting in a series of changes that occur both immediately and over time.
Direct effects on the circulatory system
Cardiac arrest
As previously mentioned, cardiac arrest is the immediate event that initiates death and brings the circulation to a standstill. Without the pumping function of the heart, the blood is no longer moved through the body, which means that the cells and organs are no longer supplied with oxygen and nutrients.
Hemostasis
With the cessation of cardiac activity, the blood flow comes to a standstill. The blood begins to pool in the dependent parts of the body under the influence of gravity, which is known as livor mortis (death spots). This discolouration typically occurs 2-6 hours after death and is a clear indication that blood circulation has stopped.
Loss of blood pressure
The immediate loss of blood pressure after cardiac arrest causes the blood vessels to lose their tension. This can lead to a visible pallor of the skin as the blood collects in the deeper parts of the body.
Long-term changes in the circulatory system
Coagulation
Shortly after death, blood begins to coagulate, which leads to the formation of blood clots. This change is a natural part of post-mortem changes but can be used in forensic medicine to estimate the time of death.
Decomposition
As time passes after death, decomposition processes begin that also affect the circulatory system. Bacteria and enzymes break down the blood and blood vessel walls, which leads to a further release of body fluids into the surrounding tissue. This process contributes to general decomposition and eventually leads to the circulatory system no longer being recognizable as such.
Changes in the blood vessels
The blood vessels themselves are also subject to post-mortem changes. Without the constant pressure of the blood flowing through them, they lose their elasticity and strength. In the course of decomposition, the blood vessels become increasingly fragile and can eventually disintegrate completely.
Forensic relevance
Examination of the circulatory system after death, including the position and condition of death marks and the nature of blood clots, can provide important forensic evidence. These can provide information about the time of death, the position of the body shortly after death and possible causes of death.
Overall, death and its effects on the circulatory system illustrate the central importance of this system for life. The immediate and long-term changes associated with the cessation of the circulatory system are essential aspects of post-mortem processes and have both biological and forensic significance.
Respiratory system
- Lungs
Death also has a profound effect on the respiratory system, which consists of the airways, lungs and muscles that support breathing. This system is responsible for gas exchange, taking oxygen from the air into the blood and releasing carbon dioxide from the blood into the air. As soon as death occurs, this vital process stops, leading to several changes.
Direct effects on the respiratory system
Breathing adjustment
The most immediate effect of death on the respiratory system is the cessation of breathing. Without the neural and muscular activities that control inhalation and exhalation, gas exchange no longer takes place. Oxygen is no longer absorbed into the blood and carbon dioxide accumulates in the blood as it is no longer exhaled.
Oxygen deficiency in the lungs
When breathing stops, the oxygen content in the lungs drops rapidly. The lungs still contain air after death, but without respiration, there is no longer any exchange of oxygen and carbon dioxide. The oxygen that is still in the lungs is partially transferred from the lungs to the blood by diffusive processes, but this amount is minimal and insufficient to support vital processes.
Changes in the lungs
After death, the lungs begin to lose their elasticity. As no new airflow is generated, the alveoli, the tiny air bubbles in the lungs that are responsible for gas exchange, can contract and partially collapse. This process contributes to the gradual stiffening of the lungs.
Long-term changes in the respiratory system
Autolysis and decomposition
As in other parts of the body, autolytic processes begin to break down the cells within the respiratory system. Enzymes present in the cells gradually break down the tissue. Over time, microbial processes further promote the decomposition of the lungs and airways. This can lead to the release of gases resulting from the breakdown of body tissues and contributes to overall putrefaction.
Changes in the composition of the air in the lungs
During decomposition, gases can accumulate in the chest as a result of the breakdown of tissue by bacterial activity. These gases can lead to visible bloating of the chest. In addition, the chemical composition of the air in the lungs changes as the gases from the decomposition process displace the air originally present.
Forensic relevance
In forensic medicine, examination of the respiratory system can provide important clues as to the cause of death. For example, water in the lungs can indicate a drowning death, while soot particles indicate smoke inhalation. The conditions of the lungs and airways can provide information about various circumstances of death and are therefore an important part of post-mortem examinations.
Overall, the effects of death on the respiratory system illustrate how essential respiration is to life and how the cessation of this system leads to irreversible changes. The post-mortem changes in the respiratory system are an integral part of the overall process of death and decomposition.
Nervous system
- Brain: The brain is particularly sensitive to a lack of oxygen. Just a few minutes after cardiac arrest, the brain cells begin to die. This leads to irreversible loss of brain functions, including consciousness and control of vital functions.
- Other nerve tissue: The peripheral nerves also suffer a similar cellular death, which means that nerve signals can no longer be sent or received.
Digestive system
- Stomach and intestines: Although the macroscopic functions of the digestive system cease, the microorganisms that live in the intestines can continue to be active and begin to break down the surrounding tissues.
- Liver and pancreas: These organs stop functioning and the enzymes they contain can begin to break down the surrounding tissue.
Musculoskeletal system
- Muscles: After death, rigor mortis causes the stiffening of the muscles caused by chemical changes in the muscle cells. This condition resolves after a few days as the decomposition progresses.
- Bones: Bones are the longest-lasting parts of the human body after death. However, they can decay or wither over time due to external influences.
Skin and sensory organs
- Skin: The skin loses its elasticity and can dry out or be decomposed by the activity of microorganisms.
- Sensory organs: The eyes dry out and can become cloudy. The other sensory organs cease to function and are also subject to the decomposition process.
Immune system
- Immune system: With the death of the host, the immune system ceases to function, which makes the body susceptible to decomposition by microorganisms.
Endocrine system
- Glands: Hormone production stops, which impairs all the regulatory mechanisms in the body that rely on it.
Death leads to an irreversible cessation of all life-sustaining processes in the body. These processes can vary depending on environmental conditions, such as temperature and humidity, as well as other factors, such as the type of death. Death and the subsequent decomposition processes are complex processes that are influenced by numerous biological, chemical and physical factors.
This article has been translated from Gentside DE.
Read more:
⋙ Rigor mortis: This is what happens in your body after you die
⋙ Blisters: The side effect of death that you probably didn't know about
⋙ The ‘death stare’: Nurse explains phenomenon that happens when a person is about to die
Sources:
Everyday Health: 10 Things Your Doctor Won’t Tell You About Dying
Very Well Health: What Physically Happens When You Die?
