Transcript document

WARM UP #3 3/30
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Settling of blood after death
Stiffening of muscles after death
Drop in temp after death
What causes our body to become stiff?
Why does blood settle after death?
Ch 3 NOTES #2
TIME OF DEATH
PART 2
3/30
PUTREFACTION –
AKA decomposition destruction of body
tissue after death
• Due to enzymes and bacteria breaking down
tissues in the body
• Studying amount of decay can give approx
time of death
SIGNS: odor, color changes, bloating
What happens to the body after
decomposition starts?
• Within 24 hours: Decomp 1st starts in the
abdomen– greenish in color
• Insects land on and feed on body
• Bacteria inside produces gas, body swells
(after 3 days body will float if in water)
• Insides continue to break down and turn into
liquid
• Blood-stained fluid comes from nose and mouth
(from gas pressure)
About 3-7 days:
* Skin slip – epidermis detaches from dermis
About 10-20 days:
• Skin rips open
• Body color darkens
Body Farm
Mummification
(under right conditions)
• Skin hardens, turns leathery
• Hair and toenails can detach
GRAVE WAX –
AKA adipocere
fat from the body can
remain after
decomposition
Skeletonization
• Only bones left - can last centuries
• Can take a few weeks – several years
Rate of decomposition depends on
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Weather
Wounds
Body size
Insects
Oxygen (decomp in air faster than soil)
Wetness
DECOMPOSTION
Decomposition of a corpse is a continual process
that can take from weeks to years, depending on
the environment.
To illustrate the process of decomposition, a
piglet is used as the corpse.
Why piglets?
• A 40 kg pig resembles a human body in its
fat distribution, cover of hair and ability to
attract insects. These factors make pigs the
next best things to humans when it comes to
understanding the process of decay of the
human body.
State of decay
A live pig is not outwardly decomposing, but its intestine
contains a diversity of bacteria.
Stage 2: Initial decay - 0 to 3 days after death
• Although the body shortly after
death appears fresh from the
outside, the bacteria that before
death were feeding on the
contents of the intestine begin
to digest the intestine itself.
They eventually break out of
the intestine and start digesting
the surrounding internal organs.
The body's own digestive
enzymes (normally in the
intestine) also spread through
the body, contributing to its
decomposition.
From the moment of death flies are attracted to
bodies. Without the normal defences of a living
animal, blowflies and house flies are able to lay
eggs around wounds and natural body openings
Stage 3: Putrefaction - 4 to 10
days after death
• Bacteria break down tissues and cells,
releasing fluids into body cavities.The
bacteria release an odor. People might find
these gases foul smelling, but they are very
attractive to a variety of insects.
• The build up of gas of the multiplying
bacteria, creates pressure within the body.
This pressure inflates the body and forces
fluids out of cells and blood vessels and into
the body cavity.
Insect activity
• The young maggots move throughout the
body, spreading bacteria and tearing tissues
with their mouth hooks.
Maggots can consume 60 per cent
of a corpse in less than a week.
Stage 4: Black putrefaction - 10 to 20 days after
death
• The bloated body eventually collapses,
leaving a flattened body whose flesh
has a creamy consistency. The exposed
parts of the body are black in colour
and there is a very strong smell of
decay.
• A large volume of body fluids drain
from the body at this stage and seep
into the surrounding soil. Other insects
and mites feed on this material.
• The insects consume the bulk of the
flesh and the body temperature
increases with their activity.
By this stage, several generations of maggots
are present on the body and some have
become fully grown. They migrate from the
body and bury themselves in the soil where
they become pupae
Stage 5: Butyric fermentation - 20 to 50 days
after death
• All the remaining flesh is
removed over this period
and the body dries out. It
has a cheesy smell, caused
by butyric acid, and this
smell attracts a new suite of
corpse organisms.
• The surface of the body
that is in contact with the
ground becomes covered
with mould as the body
ferments.
• Grave wax, or adipocere, is a
crumbly white, waxy
substance that accumulates
on those parts of the body
that contain fat - the cheeks,
breasts, abdomen and
buttocks.
• Adipocere is resistant to
bacteria and can protect a
corpse, slowing further
decomposition.
• Adipocere starts to form
within a month after death
and has been recorded on
bodies that have been
exhumed after 100 years.
Stage 6: Dry decay - 50-365 days
after death
• The body is now dry and
decays very slowly. Eventually
all the hair disappears leaving
the bones only.
decomp
Amount of food in the
digestive tract
• Food in stomach yet – ate 0-4 hours ago
• Food in small intestine – ate 4-8 hours ago
• Food in large intestine – ate 8 – 12 hours
ago
• Kind of food can show what last ate and
maybe where
• Toxicology tests for poison
Vitreous humor – clear jelly-like
liquid in the center of the eye
• Concentration of potassium (K) increases
after death
• Good for up to 72 hours
ASSIGNMENT
Find a partner to work with
Time of death scenarios