Pg.+308-322+notes+JCM

__Vocabulary__
 * Algor Mortis**: the cooling of the body after death
 * Autolysis**: the spontaneous breakdown of cells as they self-digest
 * Cause of Death**: the immediate reason for a person’s death
 * Death**: the cessation, or end, of life
 * Decomposition**: the process of rotting and breaking down
 * Forensic Entomology**: the study of insects as the pertain to legal issues
 * Instar**: one of the three larval stages of insect development
 * Larva**: immature form of an animal that undergoes metamorphosis
 * Liver Mortis**: the pooling of the blood in tissues after death resulting in a reddish color to the skin
 * Manner of Death**: one of four means by which someone dies (natural, accidental, suicidal, or homicidal)
 * Mechanism of Death**: the specific body failure that leads to death
 * Pupa**: the stage in an insect’s life cycle when the larva forms a capsule around itself and changes in its adult form
 * Rigor Mortis**: the stiffening of the skeletal muscles after death

__Introduction__ “saved by the bell” Stoppage: When the heart stops beating, cells begin to die because they no longer receive oxygen, and everything stops functioning within the body Autopsy: examination of a dead body to determine the manner, cause, and mechanism of death Manner of Death Natural death: cause by interruption and failure of body functions resulting from age or disease, most common Accidental death: caused by unplaced events Suicide: a person purposefully kills one-self Homicide: death of one person cause by another person Cause and Mechanism of Death Homicide→ bludgeoning, shooting, burning, etc. cause of death -“proximate cause of death”-refers to an underlying cause of death, as opposed to the final cause Mechanism of death→ if cause of death is shooting, mechanism is loss of blood __Liver Mortis__ -blood seeps through tissue as body decomposes over time Lividity: pooling of blood in the body • After 2 hours, it begins • After 8 discoloration is permanent • Environmental conditions effect lividity • Can reveal the position of a corpse, or if it has been moved __Rigor Mortis__ Temporary death stiffness • Starts within 2 hours of death • 12 hours body is at its most rigid state • Gradually disappears after 36, sometimes after 48 • Skeletal muscles are unable to relax 1.Ambient temperature: the cooler the body, the slower the onset of rigor 2. A person’s weight: Body fat slows down rigor mortis 3. Type of clothing: clothes accelerate rigor, naked body slows it down 4. Illness: Fever makes rigor set on faster, hypothermia slows it 5. Prior Physical Activity: if exercises or struggles, rigor sets on faster 6. Sun Exposure: A body exposed to direct sunlight will rigor faster __Algor Mortis__ Describes the temperature loss in a corpse Investigators insert thermometer into liver Expect a heat loss of approximately 1 degree F per hour Stomach and Intestinal Contents -Takes 4-6 hours to empty stomach contents to small intestine, 12 hours for it to leave intestine, 24 till it is released from large intestine 1. If undigested stanch contents are present, death occurred 0-2 hours from last meal 2. If stomach is empty, but food is found in small intestine, 4-6 hours 3. Contents in large intestine, 12 hours or more after last meal __Changes of Eye__ -eye is kept moist by blinking -thin film forms 2-3 hours if eyes were open at TOD/ 24 hours if eyes open __Stages of Decomposition__ 1. Within 2 days • cell autolysis begins following death • green and purplish staining occurs from blood decomposition • skin taken on a marbled appearance • face is discolored 2. After 4 days • skin blisters • abdomen swells with gas carbon dioxide released by bacteria 3. Within 6-10 days • corpse bloats with CO2, gas causes chest to burst and collapse • Fluids leak from body opening as cell membranes rupture • Eyeballs and other tissues liquefy • Skin sloughs off Decomposition of all tissues and organs • Depends on person’s age, size, and nature of death • Environmental conditions __Insects__ Forensic entomologist- observes and records data of temperature, moisture, and wind and collects insect evidence Wasp larva live as parasites inside the maggots, feeding on their flesh Blowflies arrive at the crime scene and exhibit different stages as they develop from the egg, larva stages (instars), pupa, to adult -First stage larva has one v-shaped slit (1.8 days old), second had 2 slits (2.5 days old), third has 3 slits (4-5 days old) • 1. If a corpse has blowfly eggs, TOD is 24 hours or less • 2. If a corpse has 3rd stage larva, TOD is 4-5 days • 3. If a corpse has pupa, TOD is 18-24 days Environmental condition→ Accumulated Degree Hours • 1. Immediately preserve some insects form the crime scene • 2. Raise some of the insects in the crime lab in same conditions • 3. Record length of time for development • 4. Compare insects raise at crime lab to crime scene If insects from another region are found on a corpse, then body was moved