Decomposition Flashcards
What are the stages of decomposition?
- Fresh
- Bloat
- Active Decay
- Advanced Decay
- Skeletonization
What are the chemical processes of decomposition?
- Early post-mortem changes
- late post-mortem changes
- autolysis
- putrefaction
- liquefaction/disintegration
- dry or skeletonized remains
What are the early-post mortem changes of decomposition?
- Loss of skin colour (pallor)
- Blood pH changes
What are the late-post mortem changes of decomposition?
- Livor Mortis
- Rigor Mortis
- Algor Mortis
Livor Mortis
Also known as lividity, this is the settling of the blood in the lower parts of the body after death. When the heart stops pumping, gravity causes the blood to pool in the lowest parts of the body, imparting a reddish-purple discolouration to the skin. Livor mortis starts developing within 30 minutes to 2 hours after death and becomes more pronounced over the next 6 to 12 hours. The pattern of livor mortis can give clues about the position of the body after death.
Rigor Mortis
This is the stiffening of muscles after death due to a lack of ATP (adenosine triphosphate), which is required for muscle relaxation. Rigor mortis typically begins within a few hours after death, starting in smaller muscles and then progressing to larger muscle groups. It peaks around 12 hours postmortem and gradually diminishes over the next 24 to 36 hours. The timing and duration of rigor mortis can vary based on factors like temperature and physical exertion before death.
Algor Mortis
This refers to the cooling of the body after death as it approaches the ambient temperature. The body temperature drops gradually until it reaches equilibrium with the environment. The rate of cooling depends on factors such as the surrounding temperature, body size, and clothing. Forensic experts can use algor mortis to estimate the time of death by measuring the body’s temperature and considering the ambient conditions.
What is autolysis?
This is the self-digestion and destruction of cells by enzymes within the body. When a person dies, cells no longer receive oxygen, and cellular membranes break down. Enzymes released during autolysis start breaking down cell structures, leading to the liquefaction of tissues.
What is putrefaction?
Bacterial activity begins due to the breakdown of cellular barriers, allowing bacteria from the digestive system and environment to proliferate. Anaerobic bacteria thrive in the absence of oxygen, producing gases such as methane, hydrogen sulfide, and ammonia. These gases cause bloating and contribute to colour changes, fluid blisters, purging of fluids and the strong odor associated with decomposition. Proceeds in optimum conditions (20-38 degrees Celsius)
What is disintegration/liquefaction?
Discoloured natural fluids and liquefied tissue. Forced from orifices by internal gas build up. Mucus sheath forms around cadaver. Liquefaction products will be incorporated into surrounding environments.
What is skeletonization?
Disintegration of soft tissue from the bone. Predominantly hard tissue remaining. Chemical and physical weathering. Fossilization or disintegration.
What is the fresh stage of decompozition?
Begins immediately after death. The body still has a normal temperature, but various chemical changes start occurring. Rigor mortis sets in, causing stiffness in the muscles.
What is the bloat stage?
Begins a few days after death. Gases produced by bacteria cause the body to swell and bloat. The skin may appear discoloured due to the gases and decomposition fluids.
What is active decay?
Starts roughly a week after death. The body begins to break down rapidly. Organs and tissues liquefy, leading to strong odors and the release of bodily fluids.
What is advanced decay?
Occurs a few weeks after death. Most of the body’s tissues have decomposed, and the body begins to dry out. The skeletonization process starts.
