2. Death
• Death is the permanent, irreversible cessation of all biological
functions that sustain a living organism. The remains of a previously
living organism normally begin to decompose shortly after death.
• Clinical signs and stages of death
1. Respiratory arrest (no breathing)
2. Cardiac arrest (no pulse)
3. Brain death (no neuronal activity)
3. Post-mortem changes
• The stages that follow shortly after death are:
• Pallor mortis, paleness which happens in the first 15–120 minutes
after death. Pallor mortis results from the collapse of capillary
circulation throughout the body.
• Algor mortis, the reduction in body temperature following death. This
is generally a steady decline until matching ambient temperature.
External factors can have a significant influence.
4. • Rigor mortis, the limbs of the corpse
become stiff (Latin rigor) and difficult to
move or manipulate.
• After death, aerobic respiration in an
organism ceases, depleting the source of
oxygen used in the making of adenosine
triphosphate (ATP). ATP is required to
cause separation of the actin-myosin cross-
bridges during relaxation of muscle. When
oxygen is no longer present, the body may
continue to produce ATP via anaerobic
glycolysis. When the body's glycogen is
depleted, the ATP concentration
diminishes, and the body enters rigor
mortis because it is unable to break those
bridges.
5. • Rigor Mortis, used to determine the time of
death.
• Starts within 2 hours after death.
• Stiffness starts in the head (eyelids) and
gradually works its way down the legs.
• The body is at the most rigid state after 12
hours.
• Stiffness disappears after 36 hours.
• It may remain up to 48 hours depending on
body weight and ambient temperature.
• Stiffness occurs because skeletal muscles are
unable to relax and remain contracted.
6. • Livor mortis, or hypostasis, is a
settling of the blood in the lower, or
dependent, portion of the body,
causing a purplish red discoloration of
the skin.
• Livor mortis starts in 20–30 minutes,
but is usually not observable by the
human eye until two hours after
death. The size of the patches
increases in the next three to six
hours, with maximum lividity
occurring between eight and twelve
hours after death.
7. • Putrefaction is the fifth stage of death,
following pallor mortis, algor mortis, rigor
mortis, and livor mortis. Putrefaction
(rotting), refers to the enzymatic
decomposition of organic material (tissue)
with production of foul-smelling
compounds (eg H2S, NH3) especially by
saprophytic / putrefactive bacteria.
• Postmortem emphysema occurs when
saprophytic bacteria produce gas, causing
gaseous distention of G-I tract, organs and
body cavities.
8. Stages of Decomposition
• A corpse decomposes in
predictable ways.
• Within 2 days after death:
• Cell autolysis begins
• Green and purplish color
occurs
• Skin takes marble appearance
• Face becomes discolor
• After 4 days:
• Skin blisters
• Abdomen swells
• Within 6 to 10 days:
• Corpse bloats
• Chest and abdomen burst and
collapse
• Fluids leak
• Eyeballs and other tissues
liquefy
• Skin sloughs off
• Decomposition = Rotting