PPTHuman Decomposition PDF
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This document presents information on the process of death and stages of decomposition. It includes details on attended and unattended deaths, and factors influencing the process, along with changes in the body after death, such as rigor mortis, livor mortis, and stages like fresh, bloated, active decay, advanced decay, and dry decay.
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The Process of Death Death is a process and not a singular event; at the time of death, the following processes occur from seconds to hours later: Heart stops beating Breathing ceases Oxygen is no longer circulated throughout the body via the bloodstream Brain dies within 3-7...
The Process of Death Death is a process and not a singular event; at the time of death, the following processes occur from seconds to hours later: Heart stops beating Breathing ceases Oxygen is no longer circulated throughout the body via the bloodstream Brain dies within 3-7 minutes without oxygen Almost always irreversible All other cells and organs begin to die off Doctors have up to 15 hours to harvest organs for donors Muscles relax The bladder and bowels release Decomposition Human Decomposition natural process involving the breakdown of tissues after death After a person dies, the circulatory system shuts down and tissue components leak out Hydrolytic enzymes are released They break down molecules into smaller molecules Bacteria begin to break down the body from the inside out Two parallel process of decomposition occur: Autolysis Self-dissolution by body enzymes released from disintegrating cells Putrefaction Decomposition changes produced by the action of bacteria and microorganisms Marked by a color change, bloating, skin slippage and a strong smell Attended Deaths If you die at the hospital or hospice care, a physician will sign off on a medical certificate on cause of death If the cause of death is unknown, the person may go off for an autopsy if the justice of the peace requests one The family can also request a private one and pay for it Some deaths are mandated for autopsies by state law For example, children under the age of 7 must have an autopsy After autopsy, the body is returned to the custody of the family via transportation to a funeral home The body is either embalmed or cremated according to the person’s wishes Decomposition does NOT occur Unattended Deaths Anytime a person dies unexpectedly or alone, the police will open up an investigation and treat it like a potential homicide In some cases, bodies are found days, months, or even years later Postmortem Time Interval (PMI) the time between death and the discovery of the body Investigators will need to know the stages of decomposition to determine the postmortem time interval By narrowing down a timeline, investigators can hone in on suspects, especially if they were the last person seen with the victim Stages of Decomposition There are five stages of decomposition: Fresh Day 0-3* Bloated Days 4-10* Active Decay Days 10-20* Advanced Decay Days 20-50* Dry Decay Days after 50* *on average but varies greatly due to many factors Fresh Stage Fresh stage decay starts immediately after death and goes until approximately day 3, but that is highly variable based on environmental factors Processes that occur during fresh stage: Pallor mortis Body with lighter skin becomes super pale after death It occurs within 30 minutes Clouding of Corneas Livor mortis Algor mortis Rigor mortis Primary flaccidity Secondary Flaccidity Face is unrecognizable after 24 hours Changes in Eyes The eyes undergo several changes postmortem The pupil dilates after death due to muscles relaxing During rigor mortis, the pupils constrict After death, the cornea changes to cloudy and opaque Cornea- clear covering on the outside front of the eye If the eyes are open upon death Cloudy cornea They become cloudy and opaque 2 hours Within 3 hours, a tache noire forms dark, red-brown stripe that develops horizontally across the eyes due to drying If the eyes are closed upon death, They become cloudy and opaque 24 hours later In addition, forensic scientists can determine potassium levels in the eye, which increase after death without being affected by temperature to get a reliable time of death Tache noire Stomach Contents After dying, the digestive system stops digesting food Investigators can determine a more accurate time of death based on where the food is located in the digestive tract This only occurs if a person ate shortly before they died Food flows from stomach to small intestine to large intestine before leaving the body If there is undigested food in the stomach death occurred 0 to 2 hours after the meal If there is undigested food in the small intestine but not stomach death occurred 4 to 6 hours after meal If there is food in the large intestine but not the small intestine or stomach death occurred 12+ hours Livor Mortis Livor Mortis Process where blood settles in lower part of body due to gravity and Livor mortis changes the skin color to red/purple Livor mortis begins approximately 20-30 minutes after death but is not seen with the naked eye until ~2 hours after death Within 8 hours it is fixed and will not change Blanching Press of the thumb against deceased’s skin to see if the livor mortis is fixed (post 8 hours) Livor mortis is valuable to investigators because it can reveal if the body was moved postmortem For example, if the person died on their back with livor mortis present on their back but is Blanching found on their stomach, it has been moved hours after death Unfixed livor mortis Algor Mortis Algor Mortis the change in body temperature post mortem, until the environment temperature is matched The body will drop on average 1.5°F every hour until the body reaches the temperature of the environment surrounding it The formula is: 98.4 – rectal temperature of body = number of hours since death 1.5 Algor Mortis is affected by: Fluctuation of environmental temperature Clothing worn- thickness, material and body coverage Surface the body is on Drugs or disease which raise body temperature before death Females are hotter compared to males due to higher body fat Infants, children and seniors cool off at a faster rate than adults Rigor Mortis Rigor Mortis Process where the muscles stiffen and is caused by chemical changes in the muscle The body, after death, is completely relaxed in the process called primary flaccidity Rigor mortis starts between ~1-4 hours after death, in the jaw and neck, with the rest of it limp It spreads to the arms and then down to the legs by approximately hour 8 In secondary flaccidity, the muscles begin to relax from rigor mortis and go limp, starting with the jaw at about hour 24 The body is limp, except for the legs, about hours 30-32 After 36 hours, the entire body is limp and it is in bloat stage Bloated Stage Beginning around day 3, the bacteria and microorganisms residing in the stomach begin to digest the tissues of the body The process excretes gases that cause the body and limbs to bloat In addition, they produce foul-smelling chemicals Putrescine, Cadaverine Around day 3, the abdomen is the first place to turn colors, Marbling from green to blue to red around day 10 Marbling can also occur on trunk, legs, arms Around day 4, skin slippage (skin shedding) occurs and purge fluid begins to come out of the nose and mouth Skin slippage at extremities is called skin degloving Active Decay Active decay occurs from approximately days 10 to 20, when putrefaction accelerates after bloating Body fluids are being actively forced out of orifices The skin will start to blacken as the tissues liquify The liquification creates a cadaver of decomposition island Area of soil and vegetation disturbed by the fluids of decomposition Maggots are actively breaking down the body mass with the Cadaver of Decomposition Island greatest amount of insect activity Active Decay ends when maggots migrate away from the body to pupate Advanced & Dry Decay Advanced Decay Approximately days 20-50 This stage marks the end of the putrefaction and the body has burst, with a caved in appearance The bones, cartilage, teeth, hair and skin remain Advanced Decay Dry Decay Days after 50 The remains are dried out and animals feed on the hair left This is a relatively short time frame since humans aren’t hairy Only the skeleton remains at this point Dry Decay Rule of Decomposition One week in air equals two weeks in water and eight weeks in soil Factors which Impact Decomposition There are many factors which impact decomposition Speeds up decomposition High humidity Higher temperature Higher levels of oxygen Larger body mass with higher levels of fat Slows down decomposition Colder temperatures Insects cannot access the body Remains are in water Remains are buried underground