I
EFFECT OF DRUGS
Certain disorders can be treated by
administration of drugs that affect the
autonomic nervous system.
Anticholiner-
gic drugs,
for example, block the effect
of acetylcholine, which can reduce mus-
cle spasms in the intestine.
Beta-blocker
drugs
block the action of adrenaline
(epinephrine) and noradrenaline (nor-
epinephrine) on the heart, thus slowing
the rate and force of the heartbeat.
autopsy
A postmortem examination of the body,
including the internal organs, which is
usually undertaken to determine the
precise cause of death. An autopsy is
sometimes required by law.
When the cause of death is known
and there are no legal requirements for
an autopsy to be carried out, hospitals
and/or doctors may seek the next-of-
kin’s permission to perform an autopsy
in order to advance knowledge of the
disease that caused death, thereby help-
ing in the care of future patients with
the same condition. Relatives are free to
refuse such consent.
autoregulation
Processes occurring within the body
that maintain ideal conditions for nor-
mal function. Such processes include
the distribution of blood between dif-
ferent organs, and balance of the body’s
salt and water content.
autosomal disorders
See
genetic disorders.
autosome
Any
chromosome
that
is
not
a
sex
chromosome. Of the 23 pairs of chro-
mosomes in each human cell,
2 2
pairs
are autosomes.
autosuggestion
Putting oneself into a receptive hypnot-
ic-like state as a means of stimulating
the body’s ability to heal itself. The idea
that symptoms could be relieved merely
through attitude was put forward by the
Frenchman Emile Coue at the end of
the nineteenth century.
Although,
autosuggestion
enjoyed
only brief popularity, some techniques
used today are based on its premise. For
example, in one method used to control
anxiety symptoms, people are taught
muscular
relaxation
techniques
(see
biofeedback
) and learn to summon up
calming imagery or pleasant thoughts.
AVIATION MEDICINE
avascular
A term meaning without blood vessels.
avascular necrosis
Cell death in body tissues as a result of
damage to the blood vessels that supply
the area.
aversion therapy
An outdated form of
behaviour therapy
in
which unpleasant stimuli, such as elec-
tric shocks, are administered at the same
time as an unwanted behaviour in an
attempt to alter behavioural patterns.
Other forms of therapy are now gener-
ally considered to be more appropriate.
aviation medicine
The medical speciality concerned with
the physiological effects of air travel,
such as the effects of reduced oxygen,
pressure
changes,
and
accelerative
forces, as well as with the causes and
treatment of medical problems that may
occur during a flight.
Aviation medicine includes assess-
ment of the fitness of the aircrew, and
sometimes of passengers, to fly, the
management of medical emergencies in
the air, the consequences of special
types of flights (such as in helicopters
and spacecraft), and the investigation of
aircraft accidents.
AIR TRAVEL-RELATED PROBLEMS
Increasing altitude causes a fall in air
pressure and with it a fall in the pres-
sure of oxygen.
Hypoxia
(a seriously
reduced oxygen concentration in the
blood and tissues) is a threat to anyone
who flies at altitude. Aviator’s
decom-
pression sickness
has the same causes as
the related condition that affects scuba
divers but it is not normally a risk for
passengers
on regular flights.
Rapid
decompression (a sudden drop in air
pressure) in civil aircraft is extremely
rare, but passengers and crew are pro-
vided with oxygen masks for use in
emergencies while the aircraft descends
to a safe altitude.
Hypoxia or, more commonly, anxiety
during flight can lead to
hyperventilation
(overbreathing),
in
which
increased
breathing results in excess loss of car-
bon dioxide. This loss alters the body’s
acidity and gives rise to symptoms such
as tingling around the mouth, muscle
spasms, and lightheadedness. If such
symptoms develop, the treatment is to
rebreathe air from a paper bag held over
the nose and mouth, which reduces the
loss of carbon dioxide.
The changes in altitude or cabin pres-
sure during a flight affect the body’s
gas-containing cavities, principally the
middle
ears,
the
facial sinuses,
the
A
CONDITIONS AFFECTING PASSENGER SUITABILITY FOR AIR TRAVEL
Conditions
Comments
Lung disease (such as chronic
The lowered cabin pressure (and thus the oxygen
bronchitis or emphysema)
level) at higher altitudes aggravates an already
impaired ability to oxygenate the blood and/or
Severe anaemia
tissues and may cause severe respiratory
distress or collapse. Seekyour doctor’s advice.
Heart condition (such as angina pectoris,
Flying may be possible if you are able to walk 50
heart failure, or recent heart attack)
metres without breathlessness or chest pain.
Recent stroke
Seekyour doctor’s advice. You may need to wait
some weeks before flying.
Recent surgery to inner or middle ear,
abdomen, chest, or brain; a recently
collapsed lung or a fractured skull.
Seekyour doctor’s advice. You may need to wait
before flying to avoid damage to your hearing
mechanism from the expansion of gas trapped in
the chest, abdomen, or skull.
Pregnancy
No flying after 34 to 36 weeks on most airlines.
Newborn baby
An infant should not fly until at least 48 hours old.
Psychiatric disorder
May need trained escort.
Infectious disease, terminal illness,
or vomiting
May be refused entry to aircraft: Check with
airline.
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