The main function of the stomach is to
contribute to the breakdown of food
that is started in the mouth and com-
pleted in the small intestine. However, it
also acts as a storage organ; if storage
were not possible, food would have to
be eaten about every 20 minutes.
The sight and smell of food, and its
arrival in the stomach, stimulate the
stomach lining to secrete gastric juice.
This fluid contains pepsin, an enzyme
that breaks down protein; hydrochloric
acid, w hich kills bacteria and creates the
p H
for pepsin activity; and
intrinsic factor, which is essential for ab-
sorption of vitamin B12 in the small
intestine. The lining also secretes mucus
to stop the stomach from digesting itself.
The layers of muscle in the stomach
about every 20 seconds that churn the
food and gastric juice. This process con-
verts semi-solid food into a creamy
fluid (chyme). At regular intervals, the
stomach muscles contract, as the pyloric
digested food into the duodenum.
s to m a c h a c h e
Discomfort in the upper abdomen. (See
in d ig e s t io n
. )
sto m a c h c a n c e r
A malignant tumour that arises from
the lining of the
s t o m a c h
The exact
e e i c o b a c t e r
p y e o r i
infection is linked to increased
risk. Other likely factors include smok-
ing and drinking alcohol. Diet may
play a part,
of salted
or pickled
foods. Pernicious
a n a e m ia
g a s -
t re c t o m y
and belonging to blood group
A also seem to increase the risk. Stom-
ach cancer rarely affects people under
4 0
and is
especially Japanese men. Symptoms may
start with loss of appetite and weight
loss; they may also be indistinguishable
from those of
p e p t ic u lc e r
and may
include burning abdominal pain, nau-
sea, and vomiting.
Diagnosis is usually made by
g a s t r o s -
c o p y
b io p s y
b a riu m X -ra y
e x a m in a tio n
Partial gastectomy may be
performed if the tumour is detected
early; otherwise, the only effective treat-
ment is gastrectomy (removal of the
stomach). In advanced cases, in w hich
the tumour has spread,
r a d io t h e r a p y
a n tic a n c e r d r u g s
may prolong life.
s to m a c h im a g in g
b a riu m X -ra y e x a m in a t io n s
s to m a c h p u m p
la v a g e , g a s t ric .
s to m a c h u lc e r
Also called a gastric ulcer, a type of
p e p t ic u lc e r
s to m a titis
Any type of inflammation or ulceration
of the mouth.
s to n e s
Small, hard collections of solid material
w ithin
c a lc u lu s ,
u r in a r y tra c t
g a lls t o n e s
. )
s to o l
Another word for
f a e c e s
in particular, a
quantity of faeces passed in one bowel
s to rk m a rk
A harmless small, flat, pinkish-red, skin
blemish found in many newborn babies,
usually around the eyes or at the nape
of the neck. Stork marks, a type of
h a e -
m a n g io m a
may be only temporary.
s tra b is m u s
A medical term for a
s q u in t
s tra ig h t le g ra is in g
A neurological test carried out during
investigation of lower-back or leg pain.
W ith the patient lying down, the leg is
fully extended and slowly raised by the
examiner, w ho aims to reach a
9 0
angle from the horizontal. The patient’s
reactions w ill be noted at each degree
of elevation. The lim it of the test is
reached, and the angle noted, when
pain is felt or the pelvis moves.
s tra in
Tearing or stretching of
m u s c le
fibres as
a result of suddenly pulling them too
far. There is bleeding into the damaged
area of muscle, causing pain, swelling,
muscle spasm, and bruising.
Treatment may include resting the
affected part (in a raised position if pos-
sible) and applying an
ic e -p a c k
to reduce
pain and swelling; taking
a n a lg e s ic d ru g s
p h y s io t h e ra p y
(See also
s p r a in
. )
s tra n g u la tio n
(usually by twisting
compression) of a tube or passage in
the body,
blood flow
interfering with the function of the
affected organ. Strangulation may occur
w ith a
h e r n ia
for example.
Strangulation of the neck is a life-
threatening accidental or deliberate in-
jury involving compression of the
ju g u -
la r v e in s
preventing blood from flowing
out of the brain, and compression of
the windpipe, w hich restricts breathing.
The victim loses consciousness; brain
damage and death caused by lack of
oxygen follow.
s tra n g u ry
A painful and frequent urge to empty
the bladder, although only a few drops
of urine can be passed. Causes include
c y s t it is
p ro s t a t it is
bladder stones (see
c a lc u lu s , u rin a ry tract
) ,
and bladder cancer (see
b la d d e r tu m o u rs
) .
s tra p p in g
The application of adhesive tape to part
of the body to exert pressure and thus
reduce pain and swelling, or to support
a weakened area.
s tra w b e rry n a e v u s
A bright red, raised spot appearing in
early infancy. Strawberry naevi are a
type of
h a e m a n g io m a
Treatment is not
usually needed unless they occur near
the eye, where they might interfere
w ith visual development.
s tra w b e rry to n g u e
A white coating with red spots that
develops on the tongue in a person
w ith
s c a rle t f e v e r
s tre p th ro a t
s t re p t o c o c c a l in fe c tio n
of the
th ro a t
is most common in children. The bacte-
ria are spread in droplets coughed or
breathed into the air.
In some people, the bacteria cause no
symptoms. In others, sore throat, fever,
and enlarged lymph nodes in the neck
occur. In some cases, the bacterial tox-
ins produce a rash (see
s c a rle t f e v e r )
Treatment is usually with a
p e n ic illin
d r u g
Untreated, strep throat may lead to
g lo m e ru lo n e p h r it is
(inflammation in the
kidneys) or
r h e u m a t ic f e v e r
s tre p to c o c c a l in fe c tio n s
caused by
b a c t e ria
of the
t r e p t o c o c c u s
spherical bacteria that grow in lines,
like beads on a string. They are among
the most common disease-causing bac-
teria in humans.
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