CELSIUS SCALE
C
CELSIUS SCALE
0°C
37
°C
100°C
32°F
98.6°F
212°F
Celsius scale
A temperature scale in w hich the melt-
ing point of ice is defined as zero
degrees (
0
°C) and the boiling point of
water is
100
degrees (
1 0 0
°C). On this
scale, the normal body temperature in
humans is
3
7
°C. The scale is named
after the Swedish astronomer Anders
Celsius (
170 1
-
1 7 4 4
). “ Centigrade” is
an obsolete name for the same scale.
To convert a Celsius temperature to
Fahrenheit, multiply the figure by
1
.
8
,
then add
3 2
. To convert Fahrenheit to
Celsius, subtract
3
2
, then multiply by
0
.
5 6
. (See also
Fahrenheit scale.)
cementum
Bonelike tissue surrounding the root of
a tooth (see
teeth).
centigrade scale
The obsolete name for the
Celsius scale
.
centrally acting
antihypertensive drugs
A type of
antihypertensive drug
used in
the
treatment
of
hypertension
(high
blood pressure). Centrally acting anti-
hypertensives,
such
as
clonidine
and
methyldopa,
act on the mechanism in
the brain that controls blood-vessel size.
central nervous system
The anatomical term for the
brain
and
spinal cord,
often abbreviated to CNS.
The central nervous system is made up
of neurons (nerve cells) and support-
ing tissue, and works in tandem with
the
peripheral nervous system
(PNS),
w hich carries signals between the CNS
and the rest of the body
The CNS receives sensory inform a-
tion from organs such as the eyes and
ears, and from sensory receptors in the
body It analyses this information, then
initiates an appropriate motor response
in the body, such as contracting a mus-
cle. (See also
nervous system.)
central venous pressure
The pressure w ithin the right
atrium,
the chamber of the heart that receives
oxygen-depleted blood from the body
Central venous pressure is measured by
means of a fine tube, attached to a
monitor, that is passed through a vein
close to the heart and into the right
atrium. By m onitoring the pressure,
doctors can estimate the volume of
blood circulating around the body This
action
may
be
of value
following
severe haemorrhage and in cases where
the blood pressure is too low to deliver
an adequate blood supply to organs
and tissues (see
shock).
centrifuge
This is a machine that separates the dif-
ferent components of a body fluid for
analysis. W hen a fluid such as blood is
spun at high speed around a central
axis, groups of particles of varying den-
sity, such as red and white blood cells,
are separated by centrifugal force and
can be analysed independently.
cephalexin
An alternative spelling of cefalexin, a
common
cephalosporin drug
.
cephalhaematoma
An extensive, soft swelling on the scalp
of a newborn baby Cephalhaematoma
is caused by bleeding into the space
between the skull and its fibrous cover-
ing (the periosteum or pericranium )
due to pressure exerted on the baby’s
head during delivery. The swelling is
neither painful nor serious and it grad-
ually subsides, although this process
may take several weeks.
Cephalhaematoma
This baby was born with a cephalhaematoma on
one side of the scalp at the back of the head. The
condition is not serious and the swelling gradually
subsides over a period of a few weeks.
cephalic
Relating to the head, as in cephalic pre-
sentation, the head-first position of a
baby in the birth canal.
cephalopelvic disproportion
A complication of childbirth (see
child-
birth,
complications of
)
in w hich the
mother’s pelvis is too narrow in pro-
portion to the size of the baby’s head.
cephalosporin drugs
COMMON DRUGS
• Cefaclor •Cefadroxil •Cefalexin •Cefotaxime
• Cefoxitin •Cefuroxime
A
large
group
of
antibiotic drugs
,
derived from the fungus C
ephaeosporium
acremonium
, w hich are effective against a
wide range of infections. Cephalospor-
ins are used to treat ear, throat, and
respiratory tract infections and condi-
tions, such as
urinary tract infections
and
the sexually transmitted infection
gon-
orrhoea,
in w hich the causative bacteria
are resistant to other types of antibiotic.
HOW THEY WORK
Cephalosporin drugs interfere w ith the
development o f bacterial cell walls and
inhibit the production of protein in the
bacterial cells. As a result, the bacteria
die. Some types of bacteria, however,
produce an enzyme (a protein that acts
as a catalyst) called beta-lactamase that
can inactivate some of the older ceph-
alosporin drugs. Newer cephalosporins
are not affected by this enzyme.
SIDE EFFECTS
Occasionally, cephalosporin drugs may
cause allergic reactions, such as rash,
itching, and fever. Rarely,
anaphylactic
shock
(a very severe allergic reaction)
occurs. Other side effects include diar-
rhoea and
blood disorders.
cerebellar ataxia
Jerky, staggering gait and other uncoor-
dinated movements caused by disease
of, or damage to, the
cerebellum.
Other
features may include
dysarthria
(slurred
speech), hand tremor, and
nystagmus
(abnormal jerky eye movements).
Causes include
stroke, multiple sclero-
sis, brain tumour,
damage as a result of
atcohot dependence,
and an inherited
disorder of the cerebellum.
cerebellar syndrome
A collection of symptoms, due to certain
types of brain disorder, that include tre-
mor, speech disturbance, and abnormal
eye movements
(
nystagmus
)
and gait.
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