Permanent cessation of all vital func-
tions. The classic indicators of death are
the permanent cessation of heart and
lung function, and, in almost all cases,
criteria by w hich
death is certified.
irreversible cessation of all functions
of the entire brain, including the
(the part of the brain that controls
involuntary actions such as breathing).
The diagnosis of death under normal
circumstances, when the individual is
not on a
is based on the
absence of breathing, absence of heart-
beat, and on the pupils being fixed
wide open and unresponsive to light.
W hen an individual has been placed
on a ventilator machine, the criteria
for diagnosing brain death are based
on clear evidence of irreversible dam-
age to the brain; persistent deep
no attempts at breathing when the
patient is taken off the ventilator; and
complete lack of brainstem function.
A noisy form of breathing resulting
from the retention of
material) in the airways of a dying per-
son w ho is no longer able to swallow it
or cough it up. Although unpleasant for
the person’s companions, it does not
appear to cause distress to him or her.
Unexpected death in a person w ho pre-
viously seemed to be healthy. The most
of sudden death in
(cessation of the
the heart muscle) may cause sudden
death at any age, and its presence may
have been unsuspected. Sudden death
may also occur as a result of
(inflammation of the heart muscle) or
Less common causes of a
sudden death include
(a severe allergic reaction), a severe
In infants, death without warning is
sudden infant death syndrome
(SIDS), or cot death.
The sudden death of a person of any
age must be reported to the coroner,
who decides whether there should be
death, sudden infant
W hen a baby is put to bed and later
found dead for no identifiable reason.
sudden infant death syndrome (SIDS)
Generalized weakness and lack of energy.
It may be due to a physical disorder
) or to a psychological
disorder (such as
Surgical removal of foreign material
and/or dead, damaged, or infected tis-
sue from a wound or burn in order to
expose healthy tissue. Such treatment
promotes the healthy healing of badly
damaged skin, muscle, and other tis-
sues in the body.
The dissolving of minerals in a tooth.
Dental decalcification is the first stage
of tooth decay. It is caused by bacteria
acting on the refined carbo-
(mainly sugars) in food to
produce acid, w hich, after prolonged
or repeated exposure, causes changes to
occur on the surface of the tooth. If the
decalcification penetrates the
layer, it spreads into the dentine and
pulp. (See also
The state of being without a function-
the main controlling part
of the brain. This situation occurs if the
is severed, w hich effectively
isolates the cerebrum.
The lining of the
the course of pregnancy. The surface
layers of the decidua are shed from the
The loss of an organ’s ability to meet
the requirements of the body. The term
“ decompensation” is usually used to
describe lessening function in an organ
that has been progressively damaged by
decompensates, it becomes unable to
maintain an adequate circulation.
The word can also be used with regard
to mental illness, as in
an individual may lose his or her usual
by w hich a person makes up for real or
matter (such as food or dead tissue)
into other chemical compounds by way
of bacterial and/or fungal action, heat,
or other processes.
A hazard of divers and of others who
work in or breathe compressed air or
other mixtures of gases. Decompression
sickness is also called “the bends” . It
results from gas bubbles forming in the
tissues and impeding the flow of blood.
At depth, divers accumulate inert gas in
their tissues from the high-pressure gas
mixture they breathe (see
avoided by allowing the excess gas in
their tissues to escape slowly into the
lungs during controlled slow ascent or
release of pressure. If the ascent is too
rapid and the pressure falls too quickly,
gas can no longer be held w ithin the
tissues and is released as bubbles.
Bubbles of gas may block blood vessels,
causing symptoms such as skin itching
I n e r t g a s d i s s o l v e d in t is s u e
f l u i d s a n d b l o o d
a n d t i s s u e s
How decompression sickness occurs
On ascent, pressure is reduced rapidly and the
gas may form bubbles that may, in turn, cause
symptoms. Divers avoid this by ascending slowly.