Exam #3 Flashcards
1
Q
What is Death?
A
- a transition rather than a distinctive point in time
- starts a series of irreversible events
- may culminate in the dissolution of the body if nothing stops or slows decomposition
2
Q
Stages of Decomposition
A
- fresh
- bloat
- active decay
- post or advanced decay
- skeletonization
3
Q
Decomposition
A
- the state or process of rotting; decay
- involves two processes:
autolysis & putrefaction
4
Q
Define Autolysis
A
- a chemical process
- cells and organs are broken down by intracellular enzymes; organs rich in enzymes autolyze fastest
- slowed by cold but accelerated by heat
5
Q
Define Putrefaction
A
- caused by bacteria and fermentation
- bacteria from GI tract invade the vascular system spreading throughout the body
- accelerated in septic individuals
- on set depends on the environment & the individual
6
Q
What is used to measure Postmortem Interval? (PMI)
A
- degree of decomposition
- livor mortis
- rigor mortis
- body temperature
- insect activity
7
Q
Livor Mortis
A
- once the heart stops blood settles into the dependent portions of the body; starts 0.5 to 2 hrs after death; is reversible until it becomes fixed 8-12hrs after death
- skin in these regions appears to turn purple or deep pink
- livor can reveal if a body has moved after death
8
Q
Rigor Mortis
A
- muscle stiffening; starts 2-4hrs after death; disappears after muscle decomposes (36+ hrs)
- caused by discontinuous supply of muscle energy source (ATP)
- without ATP muscle filaments become permanently complexed causing the muscle to stiffen
9
Q
Factors that Speed Onset
A
- exertion immediately prior to death
- high body temperature immediately prior to death
- convulsions immediately prior to death
- onset may appear to be rapid in infants
10
Q
Algor Mortis
A
- change in body temperature to match that of the external environment after death
- if the environment is colder than the body, then the body temp will drop approx. 1.5 degrees F per hr; assumes that the body temp at death was normal; assumes that the body cools at a constant rate
11
Q
Stages of Putrefaction #1
A
- greenish skin discoloration; begins 24-36hrs after death; starts in the lower quadrants of the abdomen, usually the right turns green first; followed by greenish discoloration of the head neck and shoulders
12
Q
Stages of Putrefaction #2
A
- face swells due to bacterial gas formation
- marbling; produced by hemolysis of blood in vessels; vessels near surface of skin appear dark in color
13
Q
Stages of Putrefaction #3
A
- bloating; begins 60-72hrs after death; caused by gas formation due to bacterial action; first noticeable in the face: eyes bulge tongue protrudes, face turns green then black, purge fluid may drain from mouth and nose
14
Q
Stages of Putrefaction #4
A
- vesicle formation
- skin and hair slippage
15
Q
Decomposition
A
- late stage phenomena; hair, nail, and tooth loss (weeks to months), adipocere formation (weeks to months), mummification (weeks to years), skeletonization (weeks to years)
