Death

Meaning, manner, mechanism, cause and time

Death

1. Meaning

2. Manner

3. Mechanism

4. Cause

5. Time

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 event Physiologists; when the heart stops beating, the

cells begin to die O2 levels drop Basic processes of the body fails

Nerves, muscles, organs stop working, Stoppage Once enough cellular death occurs life cannot restart

Forensic Pathologist Examination of the deceased, Autopsy

Necropsy Investigations normally are called upon when the death is:

Sudden violent unexplained deaths

Will Investigate Manner Cause And mechanism of death

of Usually preformed by a coroner/medical examiner Questions sought to answer:

Who is the victim What injuries are present When did the injuries occur Why and how were the injuries produced

Forensic PathologyAutopsy performed to establish cause of death.

Classifications the manner of Death*Natural*Homicide*Suicide*Accident*Undetermined

Manner of Death Five ways people die

1. Natural Interruption and failure of bodily function resulting from

age or disease

2. Accidental Unplanned event

3. Suicidal A person purposely kills oneself

4. Homicidal Death of one person caused by another

5. Undetermined Suicidal or accidental

Pills, guns

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.

Types of Death??? Manner of Death,

Natural, Accidental, Suicidal, Homicidal, Undetermined

Cause of death: The reason someone dies Disease: physical injury, stroke, heart attack bludgeoning, shooting, hanging suffocation,

Mechanism of Death: the specific change in the body that brought about the cessation of life

exsanguinations (Blood loss) Pulmonary arrest (Heart stoppage)

Cause and Mechanism of Death Cause of death: The reason someone dies

Disease: physical injury, stroke, heart attack Homicidal: bludgeoning, shooting, hanging

suffocation, Mechanism of Death: the specific change in

the body that brought about the cessation of life exsanguinations (Blood loss) Pulmonary arrest (Heart stoppage)

Please provide the Manner, Cause and Mechanism of Death for John Locke. Remember the season finale, he was hung.

Manner of Death Cause of death Mechanism of Death

Please provide the Manner, Cause and Mechanism of Death for John Locke. Manner of Death: Homicide

Cause of death: hanging suffocation, (asphyxia)

Mechanism of Death: hypoxia, reduction of oxygen supply to a tissue

Time of Death

Livor Mortis Rigor Mortis Algo Mortis

Homework:Research and Identify How investigators estimate time of death..There are about 9 ways

Estimating Time of Death9 Ways of Estimating 9 Ways of Estimating ActualActual Time of Death: Time of Death:

http://www.dundee.ac.uk/forensicmedicine/llb/timedeath.htm#Time%20of%20Death

1. Rigor mortis2. Livor mortis: (Lividity) 3. Algor mortis: Body Core Temperature4. Potassium levels in vitreous humor + Clouding

of the cornea5. Stomach Contents6. Evidence of Decompositional Process7. Presence/absence of purge fluids8. Drying of the tissue 9. Insect Larval Instars

Algor Mortis 1. 1. Algor mortisAlgor mortis

• the reduction in body temperature following death. • a steady decline until matching ambient temperature • A 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 Newton's law of cooling states that the rate of cooling of a body is determined by the difference between the body is determined by the difference between the temperature of the body and that of its environment. temperature of the body and that of its environment.

• The Glaister equation: 1-1 1/2 degree F per hour

• Algor 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?????

1. Algor mortisAlgor mortis (L: algor—coolness; ath)

Questions: What are some Factors that would affect Algor Mortis? Ambient temperature Wind? Excess body fat? Clothing etc

2. Rigor Mortis (L: rig- stiff; mortis—death) Muscles become rigid Starts w/I 2 hours but gone after 48 hours After 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.”

2. Rigor MortisTime Event Appearance

2-6 hours Rigor begins eyelids, Jaws stiffen

After 2 hours

then center of body stiffens

12 hours Complete Rigor Entire body rigid

15-36 Slow loss of rigor, small muscles first

Lost in head and neck, last is bigger leg muscles

36-48 Rigor disappears, muscles become relaxed

2. What are some factors affecting Rigor mortis ?Rigor mortis ? 1.Ambient temperature,

Cooler the body the slower to onset of rigor 2.Person’s weight

fat stores more oxygen and slow rigor3. Type of clothing

Helps keep the body warm4. Illness

Dies with a fever? What would you expect? Hypothermic? What would you expect?

5.Level of physical activityStruggling before death rigor, What would you expect?

6.Sun exposure, Sun tanner? What would you expect?

Live muscles fiber slide back and forth; in 48 hours after death, the muscles become locked in a fixed position

or 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,

3. Livor mortis

3. Livor mortis

Special thanks to

http://classjump.com/dizengoff/documents/6929652646.pdf

4. Rate of Decay

4. Rate of Decay

5. Stomach Contents

6. Entomology

6. Entimology

Blow Fly Life cycle

Total time 16 to 35

6. Entomology Flies

Total time 16 to 35

6. Entomology Beetles

The sexton beetle, Nicrophorus orbicollis.  The sexton beetles are generally nocturnal and are typically found under a body or in the soil immediately surrounding the remains during the daylight hours. 

The 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.  

7. Potassium levels in Vitreous humor and clouding cornea

8. Presence/absence of purge fluids9. Drying of the tissue

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 Dry Decay

Corpse is almost dry, further decay slows from lack of moisture

Guess the Stage of Decomposition

Stages of Decomposition 2 days

Cells autolysis 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

The-