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Death

Death. Meaning , Manner , Mechanism , Cause and Time. How Do we Define Death?. Is a person with a heartbeat alive even if there is no brain activity ?. How do we define Death ?. Death is a process not an event Physiologists; when cells begin to die O 2 levels drop no ATP

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Death

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  1. Death Meaning, Manner, Mechanism, Cause and Time

  2. How Do we Define Death? Is a person with a heartbeat alive even if there is no brain activity?

  3. How do we define Death? Death is a process not an event Physiologists; when cells begin to die O2 levels dropno ATP Basic processes of the body fails Nerves, muscles, organs stop working… Once enough cellular death occurs life cannot restart

  4. Forensic Pathologist Examination of the deceasedAutopsy when the death is: Sudden violent unexplained deaths Investigators will look into Manner Cause mechanism of death Questions sought to answer: Who is the victim What injuries are present When did the injuries occur Why and how were the injuries produced

  5. Manner of Death Natural death resulting from age or disease Accidental Unplanned event Suicidal Intentionally killing oneself Homicidal Death of one person caused by another Undetermined Suicidal or accidental?? Pills, guns

  6. Cause and Mechanism • Cause of death • Reason someone dies: • Heart attack, gunshot, infection, disease • Mechanism of Death-body failure • Loss of blood (exsanguination) • Loss of oxygen (asphxia)

  7. Time of Death

  8. Estimating Time of Death • Rigor mortis-Stiffness of Death • Livor mortis: (Lividity)-Color of Death • Algor mortis: Body Core Temperature • Potassium levels in vitreous humor + Clouding of the cornea • Stomach Contents • Evidence of Decomposition • Insect

  9. Algor Mortis body temperature Normal body temperature is 370C (98.60F) A body loses heat at a rate of 1.40F perhour until the ambient temperature is reached (Rate varies) Once ambient temperature is reached, you cannot use this method to determine time of death

  10. Question: What are some Factors that would affect Algor Mortis?

  11. Rigor mortis: • The stiffness begins 2 hours after death • Oxygen is needed for muscle relaxation.

  12. Rigor Mortis

  13. Figure 49.31 The structure of skeletal muscle

  14. What are some factors affecting Rigor mortis ? • Ambient temperature, • Cooler the body the slower the onset of rigor • Person’s weight • Fat stores more oxygen and slow rigor • Type of clothing • Helps keep the body warm • Illness • Dies with a fever? What would you expect? • Hypothermic? What would you expect? • Level of physical activity • Struggling before death rigor, What would you expect?

  15. Livor mortis * Lividity -settling of the blood in the lower portion of the body *** Discoloration does not occur in the areas of the body that are in contact with the ground or another object Begins 2 hours after death and permanent after 8 hours Dual lividity-indicates a change in position prior to becoming fixed

  16. 3. Livor mortis

  17. Potassium levels Clouding of the cornea Cornea is the clear covering of your eyes Becomes cloudy and opaque after death Takes only a few hours after death if eyes are open at death It takes 24 hours if eyes are closed at death.

  18. Digestion provides clues *stomach empties around 4-6 hours after last meal *If NO food is in stomach-how long ago did death occur? *small intestines empties after approx. 24 hours after last meal *large intestines empties after approx. 48-72 after last meal

  19. Stages of Decomp

  20. Stages of Decomposition Initial decay Corpse appears normal, internal bacterial decay and autolysis begins Putrefaction Odor of decaying corpse swollen Black Putrefaction Very strong odor, flesh appears black, gases escape, corpse collapses Butyric Fermentation-drying,cheesy smell Dry Decay Bone and Hair. (without water, limited bacterial action)

  21. Stages of Decomposition 2 days Cells autolysis-cell death Greenish purple staining occurs, blood decomposing Skin takes on Marbled Appearance 4 days Skin blisters Abdomen swells with carbon dioxide Due to bacteria in intestines 6-10 days Corpse bloats with CO2 Corpse eventually bursts Fluid begins leaking from openings as cell membranes rupture Eyeballs liquefy Skin sloughs off

  22. Forensic entomology Entomology is study of insects Used for a large variety of instances Insects and human remains Damage to property for a civil suit Insects and injuries in abuse cases

  23. Life cycles of insects is important to understand time of death * complete metamorphosis (egg, larva, pupa, adult) Fly larva are called maggots Determining stages will help tell time of death

  24. Complete Metamorphosis

  25. Fly Pupa

  26. Adult fly emerging from pupa

  27. Blowflies are usually the 1st invader Can lay eggs within 20 minutes of death

  28. Other uses of Insects Can do DNA analysis on the victim ingested by insect Can do toxicological analysis Wound location

  29. Types of Injury • Antemortem-before death. Signs of healing • Perimortem-near time of death. No healing • Postmortem-after death. Discolored,bones break easier(bite marks, crushing)

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