INTERVERTEBRAL DISC
INTESTINE, OBSTRUCTION OF
is most common in obese people. The
affected skin is red and moist and may
have an odour, often with a fungal infec-
tion such as
candidiasis
;
there may also
be scales or blisters. The condition wors-
ens with sweating. Treatment consists of
weight reduction and keeping the affected
areas clean and dry. A cream containing
a
corticosteroid
and/or
antifunga drug
is
used if candidiasis is present.
intervertebral disc
See
disc, interver-
tebral
.
intestinal imaging
See
barium X-ray
examinations
.
intestinal lipodystrophy
See
Whip-
ple's disease
.
intestine
The major part of the digestive
tract (see
digestive system
), extending
from the exit of the stomach to the anus.
It forms a long tube divided into 2 main
sections: the small and large intestines.
The small intestine is about 6.5 m in
length and has 3 sections: the
duode-
num
,
the
jejunum
and the
ileum
.
Partially
digested food from the stomach is
forced along the intestine by
perist
a
sis.
The small intestine is concerned with
the digestion and absorption of food.
Digestive enzymes and bile are added to
the partly digested food in the duodenum
via the bile and pancreatic ducts (see
biliary system
). Glands within the walls of
each section of the small intestine pro-
duce mucus and other enzymes, which
help to break down the food. Blood
vessels in the intestinal walls absorb
nutrients and carry them to the liver for
distribution to the rest of the body.
The large intestine is about 1.5 m long.
The main section, the
colon
, is divided
into an
ascending,
a transverse,
a
descending, and a pelvic portion (the
sigmoid colon). The
appendix
hangs from
a pouch (the
caecum
) between the small
intestine and the colon. The final sec-
tion before the
anu
s is the
rectum
.
Unabsorbed material leaves the small
intestine as liquid and fibre. As this
material passes through the large intes-
tine, water, vitamins, and mineral salts are
absorbed into the bloodstream, leaving
faeces made up of undigested food resi-
due, fat, various secretions, and bacteria.
The faeces are compressed and pass
into the rectum for evacuation.
intestine, cancer of
A malignant tumour
in the intestine. Both the small and large
intestine may develop carcinoid tumours
(leading to
carcinoid syndrome
) and
lymphomas
. Cancer of the small intestine
is rare, but cancer of the large intestine is
one of the most common of all cancers
(see
colon, cancer of
;
rectum, cancer of
).
intestine, disorders of
The intestine is
subject to various structural abnormali-
ties and to the effects of many infective
organisms and parasites; it may also be
affected by tumours and other disorders.
Structural abnormalities may be pre-
sent from birth (congenital) or may
develop later. They cause blockage of the
intestine (see
intestine, blockage
of) and
include
atresia
,
stenosis
,
and
volvulus
.
In
newborns, meconium (fetal intestinal
contents) may block the intestine.
Generalized inflammation of the intes-
tine may result from viral or bacterial
infections or from noninfectious causes,
as in
ulcerative colitis
and
Crohn's disease
.
G
astroenteritis
is the term commonly ap-
plied to inflammation of the stomach and
intestines. Infection encompasses
food
poisoning
,
traveller's diarrhoea
,
typhoid
fever
,
cholera
,
amoebiasis
,
and
giardiasis
.
Intestinal worm infestations include
roundworms
and
tapeworms
.
Some-
times inflammation is localized, such as
in
appendicitis
and
diverticular disease
.
Tumours of the small intestine are rare,
but noncancerous growths,
lymphomas
,
and carcinoid tumours (causing
carcinoid
syndrome
) occur. Tumours of the large
intestine are common (see
colon, cancer
of; rectum, cancer
of). Some forms of
familial
polyposis
may progress to cancer.
Impaired blood supply (
ischaemia
) to
the intestine may occur as a result of
partial or complete obstruction of the
arteries in the abdominal wall (from dis-
eases such as
atherosclerosis
) or from
the blood vessels being compressed or
trapped, as in
intussusception
or
hernias
.
Loss of blood supply may cause
gangrene
.
Other disorders that affect the intestine
include
peptic ulcers
,
diverticulosis
,
mal-
absorption, coeliac disease
, and
irritable
bowel syndrome
.
intestine, obstruction of
A partial or
complete blockage of the small or large
intestine. Causes include a strangulated
314
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