CARDIOTOCOGRAPHY
C
Brain damage is likely if the brain is
starved of blood, and therefore oxygen,
for more than three to four minutes.
First, mouth-to-mouth resuscitation
(see
rescue breathing
)
is given in order
to restart the casualty’s breathing. If this
step fails, repeated chest compressions,
using the heel of the hand, are applied
to the lower part of the breastbone (see
external cardiac massage
)
until
emer-
gency
medical
help
arrives.
These
measures are used alternately to restore
blood circulation to the brain.
cardiotocography
See
fetal heart monitoring
.
cardiovascular
A term that means “ pertaining to the
heart and blood vessels” .
cardiovascular disorders
Disorders of the heart (see
heart
disor-
ders box), blood vessels, and blood
circulation
(see
arteries,
disorders of
;
veins, disorders of
) .
cardiovascular surgery
The branch of surgery that is con-
cerned
with
the
heart
and
blood
vessels. Cardiovascular surgery can be
divided into two main areas.
One area, sometimes called cardio-
thoracic surgery, includes operations to
prevent or repair damage to the heart
itself and to the major blood vessels
w ithin the chest cavity. Cardiothoracic
surgery is used, for example, to help
treat damage due to congenital heart
disease (see
heart disease, congenital
)
or
a
myocardial infarction
(heart attack).
The second area, w hich is known as
vascular surgery, is concerned with the
treatment of blood vessels elsewhere in
the body, such as in the legs. (See also
heart valve surgery
,
coronary artery bypass
,
and
heart transplant
. )
cardioversion
An alternative name for
defibrillation
.
carditis
A general term for inflammation of any
part of the heart or its linings. There
are three types.
Myocarditis
(inflamma-
tion of the heart muscle)
is usually
caused by a viral infection.
Endocarditis
(inflammation of the internal lining of
the heart) is usually due to a bacterial
infection.
Pericarditis
(inflammation of
the outer covering of the heart) is usu-
ally the result of a viral or bacterial
infection but may be associated with a
myocardial infarction
(heart attack) or an
autoimmune disorder, such as systemic
lupus erythematosus
.
caries, dental
The gradual erosion of enamel
(the
hard covering of a tooth) and dentine
(the softer substance that lies beneath
the enamel). This condition is more
commonly known as tooth decay.
CAUSES
The main
cause
of dental caries is
plaque
,
a sticky substance consisting of
food deposits, saliva by-products, and
bacteria that collects on the surface of
teeth. The breakdown of food deposits
by bacteria creates acid that eats into
the enamel to form cavities. Left un-
checked, decay spreads to the dentine,
and as the cavity enlarges, bacteria may
invade and destroy the pulp tissue at
the core of the tooth.
SYMPTOMS
Initial
decay
usually
occurs
on
the
grinding surfaces of the back teeth and
on areas around the gum line. In the
early stages, dental caries does not usu-
ally
cause
any
symptoms. Advanced
decay causes toothache (see
pulpitis
) ,
however, w hich may be aggravated by
eating very sweet, hot, or cold food.
Sometimes advanced decay can also
cause halitosis (bad breath).
TREATMENT
Treatment consists of drilling away the
area of decay and filling the cavity (see
filling, dental
). In advanced decay, it may
be necessary to remove the infected
pulp and replace it with a filling (see
root-canal treatment
)
or to extract the
tooth (see
extraction, dental
).
PREVENTION
The risk of dental caries occurring is
reduced by cutting down on sugar con-
sumption, practising good
oral hygiene,
and visiting the dentist regularly. Water
fluoridation
and
the
use
of fluoride
toothpaste also helps to prevent caries.
carminative
A
medicine
that
relieves
abdominal
w ind
(
flatulence
) .
Carminatives are used
in the treatment of
colic
.
CAUSES OF CARIES (TOOTH DECAY)
The primary cause of tooth decay is
dental
plaque,
a sticky substance that
forms on the teeth. Plaque consists of
food remains, saliva by-products, and
the bacteria that live in the mouth. The
bacteria feed mainly on the fermentable
carbohydrates (simple sugars and
starches) in food, and, in breaking them
down, create an acid that gradually
destroys enamel, forming a cavity. If the
process is not checked, the dentine is
eroded next, enlarging the cavity and
enabling the bacteria to invade the
pulp at the centre of the tooth.
Micrograph of dental caries
The surface enamel of this decaying molar tooth
is being broken down.
E n a m e l
I
Acid produced
in the break-
down offood
gradually destroys
enamel, forming
a cavity.
D e n t i n e
2
Unchecked,
decay spreads
to the dentine.
P u lp c a v it y
3
The cavity
continues to
enlarge, enabling
the bacteria to
invade exposed
pulp at the
tooth’s centre.
4
If untreated, the
infected pulp will
die and the tooth
will be destroyed.
146
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