3 How do we define Death?Is a person with a heartbeat alive even if there is no brain activity?Death is a process not an eventPhysiologists; when the heart stops beating, the cells begin to dieO2 levels dropBasic processes of the body failsNerves, muscles, organs stop working, StoppageOnce enough cellular death occurs life cannot restart
4 Forensic Pathologist Examination of the deceased, Autopsy NecropsyInvestigations normally are called upon when the death is:Suddenviolentunexplained deathsWill InvestigateMannerCauseAnd mechanism of deathof Usually preformed by a coroner/medical examinerQuestions sought to answer:Who is the victimWhat injuries are presentWhen did the injuries occurWhy and how were the injuries produced
5 Forensic Pathology Autopsy performed to establish cause of death. Classifications the manner of Death*Natural*Homicide*Suicide*Accident*Undetermined
6 Manner of Death Five ways people die Natural Accidental Suicidal Interruption and failure of bodily function resulting from age or diseaseAccidentalUnplanned eventSuicidalA person purposely kills oneselfHomicidalDeath of one person caused by anotherUndeterminedSuicidal or accidentalPills, guns
7 Do Now: Identify what is the Manner of Death? Case 1: A man with a heart condition is attacked and dies from a heart attack during the assault.Case 2: An elderly woman dies after being kept from receiving proper health care by her son.
8 Types of Death??? Manner of Death, Natural, Accidental, Suicidal, Homicidal, UndeterminedCause of death: The reason someone diesDisease: physical injury, stroke, heart attackbludgeoning, shooting, hanging suffocation,Mechanism of Death: the specific change in the body that brought about the cessation of lifeexsanguinations (Blood loss)Pulmonary arrest (Heart stoppage)
9 Cause and Mechanism of Death Cause of death: The reason someone diesDisease: physical injury, stroke, heart attackHomicidal: bludgeoning, shooting, hanging suffocation,Mechanism of Death: the specific change in the body that brought about the cessation of lifeexsanguinations (Blood loss)Pulmonary arrest (Heart stoppage)
10 Please provide the Manner, Cause and Mechanism of Death for John Locke. Remember the season finale, he was hung.Manner of DeathCause of deathMechanism of Death
11 Please provide the Manner, Cause and Mechanism of Death for John Locke. Manner of Death: HomicideCause of death: hanging suffocation, (asphyxia)Mechanism of Death: hypoxia,reduction of oxygen supply to a tissue
12 Time of DeathLivor MortisRigor MortisAlgo Mortis
13 Homework: Research and Identify How investigators estimate time of death.. There are about 9 ways
14 Estimating Time of Death 9 Ways of Estimating Actual Time of Death:Rigor mortisLivor mortis: (Lividity)Algor mortis: Body Core TemperaturePotassium levels in vitreous humor + Clouding of the corneaStomach ContentsEvidence of Decompositional ProcessPresence/absence of purge fluidsDrying of the tissueInsect Larval Instars
16 1. Algor mortis (L: algor—coolness; ath) the reduction in body temperature following death.a steady decline until matching ambient temperatureA measured rectal temperature can give some indication of the time of death.Newton's law of cooling states that the rate of cooling of a body is determined by the difference between the temperature of the body and that of its environment.The Glaister equation: /2 degree F per hourAlgor mortis is usually the first sign of death, beyond the obvious, and is then followed by rigor mortis. As decomposition occurs the internal body temperature tends to rise again. WHY?????
17 Questions: What are some Factors that would affect Algor Mortis? Ambient temperatureWind?Excess body fat?Clothingetc
18 2. Rigor Mortis (L: rig- stiff; mortis—death) Muscles become rigid Starts w/I 2 hours but gone after 48 hoursAfter 48 hours muscles begin to autolysis (dissolve)“The biochemical cause of rigor mortis is hydrolysis of ATP in the muscle tissue, the chemical energy source required for movement. Myosin molecules devoid of ATP become permanently adherent to actin filaments and muscles become rigid.”
19 2. Rigor Mortis Time Event Appearance 2-6 hours Rigor begins eyelids, Jaws stiffenAfter 2 hoursthen center of body stiffens12 hoursComplete RigorEntire body rigid15-36Slow loss of rigor, small muscles firstLost in head and neck, last is bigger leg muscles36-48Rigor disappears, muscles become relaxed
20 2. What are some factors affecting Rigor mortis ? Ambient temperature,Cooler the body the slower to onset of rigorPerson’s weightfat stores more oxygen and slow rigorType of clothingHelps keep the body warmIllnessDies with a fever? What would you expect?Hypothermic? What would you expect?Level of physical activityStruggling before death rigor, What would you expect?Sun exposure,Sun tanner? What would you expect?
21 Live muscles fiber slide back and forth; in 48 hours after death, the muscles become locked in a fixed position
22 3. Livor mortis or (postmortem lividity) L: liv-bluish) * Is a settling of the blood in the lower portion of the body** Causing a purplish red discoloration of the skin.*** Discoloration does not occur in the areas of the body that are in contact with the ground or another object,
34 6. Entomology BeetlesThe American carrion beetle, Necrophila americana. Although this beetle is primarily nocturnal,it is commonly observed on the upper surfaces of a body during the daylight hours. Large aggregations of these beetles have been observed, and they can sometimes be as numerous as flies. The sexton beetle, Nicrophorus orbicollis. The sexton beetles are generally nocturnal andare typically found under a body or in the soil immediately surrounding the remains during the daylight hours.
35 7. Potassium levels in Vitreous humor and clouding cornea
36 8. Presence/absence of purge fluids 9. Drying of the tissue
37 Stages of Decomposition Initial decayCorpse appears normal, internal bacterial decay and autolysis beginsPutrefactionOdor of decaying corpse swollenBlack PutrefactionVery strong odor, flesh appears black, gases escape, corpse collapsesDry DecayCorpse is almost dry, further decay slows from lack of moisture
39 Stages of Decomposition 2 daysCells autolysisGreenish purple staining occurs, blood decomposingSkin takes on Marbled Appearance4 daysSkin blistersAbdomen swells with carbon dioxideDue to bacteria in intestines6-10 daysCorpse bloats with CO2Corpse eventually burstsFluid begins leaking from openings as cell membranes ruptureEyeballs liquefySkin sloughs off