Death: Meaning, Manner, Mechanism, Cause and Time

Forensics: DeathName:

Ch. 11 Hour: 1, 2, 3, 4, 5, 6, 7

Pages 308 - 323

Death: meaning, Manner, Mechanism, Cause and Time

1. Explain where the term “Saved by the bell” originated.

2. Autolysis is where the cell breaks down, explain what occurs during autolysis.

The cell membrane dissolves, enzymes and other cell contents spill out and digest the surrounding tissue.

3. When is an autopsy conducted?

To determine the manner, cause and mechanism of death.

4. List and describe 5 different “Manner of death” or ways in which a person can die.

Natural death – caused by an interruption and failure of body function resulting from age or disease.
Accidental death – caused by unplanned events. i.e. car accident
Suicidal death – where the person purposefully kills themselves.
Homicidal death – death of a person caused by another person
Undetermined – Unknown

5. Give examples of death that might be caused by homicide.

Bludgeoning, shooting, burning, drowning, strangulation, hanging, suffocation.

6. What is mean by proximate cause of death? Example?

Refers to an underlying cause of death. I.e. exposed to radiation – causes cancer.

7. Mechanism of death is the specific body failure that leads to death, give at least two
examples.

Shooting – caused by loss of blood.

Heart attack – heart stopped

8. Answer the following that are used to approximate the time of death.

a. Define liver mortis:

The pooling of blood in tissue after death resulting in a reddish color to the skin.

b. This is known as lividity which gives clues to how long the person has been dead.

How long after death does lividity set in?

2 hours

c. When does the discoloration become permanent?

8 hours

d. How can lividity be used to determine how long a person has been dead?

Between 2 & 8 hours – if skin is pressed, lividity will disappear.

More than 8 yours lividity remains.

e. It is important to record the environmental conditions surrounding a dead
body. Explain how the ambient temperature at the time of death impacts lividity.

Outside on a hot day will speed up lividity.

At room temperature it will occur more slowly.

f. List other clues that are provided at the time that livor mortis sets in.

Position of the corpse

If the body was moved.

g. What is rigor mortis?

Stiffing of the skeletal muscles after death.

h. Give the time for the following situations:

Rigor mortis starts within -2 hours

The most rigid state is at:12 hours

Rigor mortis disappears:after 36 hours to 48 hours

i. Name two things that might cause rigor to remain for 48 hours.

Weight and temperature

j. How do you know when the body is likely to be losing its rigor?

No rigor in the face but some still in the body.

k. Name six factors that affect when rigor mortis sets in.

Ambient temperature

Person’s weight

Type of clothing

Illness

Level of physical activity shortly before death

Sun exposure

9. What is algor mortis?

The cooling of the body after death.

10. The temperature of the body is taken by the forensic scientist in what organ? Why?

Liver, because having a standard location for taking the body temperature ensures that investigators can compare their results.

11. What is the approximately rule of thumb to determine how long a body has been dead
by using their internal temperature?

1 degree F per hour .78 Degrees C per hour; .39 degrees after 12 hours.

12. Explain how the stomach and intestinal content can be used to determine the time
of death.

Stomach 2 – 6 hours
Takes about 6 hours for the stomach to empty its contents into the small intestine.

12 hours for food to leave the small intestine.

24 hours before it is released from the large intestine.

13. Explain how the eye of a person can help determine the time of death.

The surface of the eye dries with 2 to 3 hours if the eyes are open, or 24 hours if the eyes are close.

A build up of potassium occurs within the vitreous humor.

14. Explain what the body looks like during its stages of decomposition in the following
time periods.

Within 2 days:

-Cell autolysis begins following death

-Green & purplish staining occurs from blood decomposition

-Skin takes on a marbled appearance

-Face becomes discolored.

After four days:

-Skin blisters

-Abdomen swells with the gas carbon dioxide that is released by bacteria living in the intestine.

Six to ten days.

-The corpse bloats with carbon dioxide as bacteria continues to feed on tissues. Eventually, the gas caused the chest and abdominal cavities to burst and collapse.

-Fluid begins to leak from the body openings as cell membranes rupture.

-Eyeballs and other tissues liquefy

-Skin sloughs off.

15. Who decomposes the quickest?

a. Young or old?Young

b. Overweight or normal size people?Overweight

Naked or clothes?Naked

d. Sick or healthy?Sick

16. Explain how the following environmental conditions affect the decomposition or a
body.

70 to 99 degrees:Fastest rate of decomposition

over 100:Tends to dry out the corpses, preserves them.

Lower temperatures:Tend to prevent bacterial growth and slow down decomposition.

Moist conditions:If rich in oxygen, decomposition is sped up.

If in water or buried - slower

17. Forensic entomology is:

The study of insects as they pertain to legal issues.

18. Explain how insects are used to determine the time of death.

Insects arrive and lay their eggs.

Eggs hatch and feed on the decomposing tissues.

Blowfly: Attracted by two gases putrescine and cadaverene.

Tiny wasp: Lay eggs inside the maggots.

Cheese skippers – Attracted by the seepage of body fluids.

19. Name different bugs, the time it will appear and what attracts the bug to the body
during the stages of decomposition.

Blowfly eggs – 24 hours or less

third-stage larvae – 4 to 5 days

If corpse contains pupae – 18 to 24 days.

20. What is putrefaction?

Putrefaction - decay