RESPIRATION
RESPIRATORY SYSTEM
inflammation of surrounding tissues, or
pressure, for example from an impacted
tooth. Internal resorption is rare, occur-
ring in about
1
percent of adults.
respiration A term for the processes by
which
oxygen
reaches body cells and is
utilized by them, and by which
carbon
dioxide
is eliminated. Air, containing
oxygen, is breathed into the
lungs
and
enters the
alveoli
. Oxygen diffuses into
the blood, which carries it to cells in the
body, where it is used to metabolize
glucose
to provide energy. Carbon diox-
ide is produced as a waste product and
passes into the blood from the body
cells. It is transported to the lungs to be
breathed out (see
respiratory system).
respirator See
ventilator.
respiratory arrest Sudden cessation of
breathing,
resulting from any process
that severely depresses the function of
the respiratory centre in the
brain.
Causes
include prolonged
seizures
, an overdose
of
opioid drugs
,
cardiac arrest
,
electrical
injury
, serious
head injury
,
stroke
, or
res-
piratory failure.
Respiratory arrest leads
to
anoxia
and, if untreated, cardiac arrest,
brain damage,
coma,
and death.
respiratory distress syndrome An
acute lung disorder that makes
breathing
difficult, resulting in a life-threatening
deficiency of
oxygen
in the blood. There
are 2 types of the syndrome. In prema-
ture babies, the lungs are stiff and do
not inflate easily due to a lack of
surfac-
tant
. In adults, it develops as a result of a
severe injury or overwhelming infection.
Treatment is for the underlying cause,
and is with artificial
ventilation
and oxy-
gen; inhaled surfactant is given to babies.
respiratory failure A condition in which
there is a buildup of
carbon dioxide
and
a fall in the level of
oxygen
in the blood
(see
hypoxia
). Causes include lung disor-
ders, such as severe
asthma
,
emphysema
,
or chronic bronchitis (see
pulmonary dis-
ease, chronic obstructive
), or damage to
the respiratory centre in the brain due
to, for example, an overdose of
opioid
drugs,
a
stroke,
or serious
head injury.
Treatment is with
ventilation
and oxy-
gen for the underlying cause.
respiratory function tests See
pul-
monary function tests
.
respiratory system The organs respon-
sible for carrying
oxygen
from the air to
the blood and expelling
carbon dioxide.
The upper part of the
respiratory system con-
sists of
2
nasal passages;
the
pharynx
; the larynx
(which
contains
the
vocal cords); and the
trachea.
The lower part
of the respiratory tract
consists of two
lungs
,
which are enclosed in a
double membrane called
the
pleura
, and the lower
airways (the
bronchi
and
smaller
bronchioles).
These
structures
are
encased and protected
by the bony ribcage. The
airways
terminate
in
millions of balloon-like
sacs known as
alveoli
,
where
gas
exchange
with the tiny blood ves-
sels surrounding them
takes place. These small
vessels feed into larger
R
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