ADENOIDECTOMY
ADIPOSE TISSUE
form gland-like structures. An adeno-
carcinoma arises from epithelium (the
layer of cells that lines the inside of
organs). Cancers of the colon, breast,
pancreas, and kidney are usually adeno-
carcinomas, as are some cancers of the
cervix, oesophagus, salivary glands, and
other organs. (See also
intestine, cancer
of; kidney cancer; pancreas, cancer of.)
adenoidectomy Surgical removal of the
adenoids.
An adenoidectomy is usually
performed on a child with abnormally
large adenoids that are causing recur-
rent infections of the middle ear or air
sinuses. The operation may be perfor-
med together with
tonsillectomy.
adenoids A mass of glandular tissue at
the back of the nasal passage above the
tonsils. The adenoids are made up of
Ij
rniph nodes,
which form part of the
body's defences against upper respira-
tory
tract infections;
they
tend
to
enlarge during early childhood, a time
when such infections are common.
ADENOIDS
Adenoids
Nasal cavity
Tongue
Tonsils
Opening of
eustachian
tube
Pharynx
In most children, adenoids shrink after
the age of about 5 years, disappearing
altogether by puberty. In some children,
however,
they
enlarge,
obstructing
breathing and blocking the eustachian
tubes, which connect the middle ear to
the throat. This results in recurrent
infections and deafness. Infections usu-
ally respond to
antibiotic drugs,
but if
they recur frequently, adenoidectomy
may be recommended,
adenoma A non cancerous tumour or
cyst that resembles glandular tissue
and arises from the epithelium (the
layer of cells that lines the inside of
organs). Adenomas of
endocrine glands
can cause excessive hormone produc-
tion, leading to disease. For example,
pituitary gland adenomas can result in
acromegaly
or
Cushing's s^mdrome.
adenomatosis An abnormal condition
of glands in which they are affected
either by
hyperplasia
(overgrowth) or
the development of numerous
adenomas
(noncancerous tumours). Adenomato-
sis may simultaneously affect 2 or more
different
endocrine glands.
ADH The abbreviation for antidiuretic
hormone (also called vasopressin), which
is released from the posterior part of
the
pituitary gland
and acts on the kid-
neys to increase their reabsorption of
water into the blood. ADH reduces the
amount of water lost in the urine and
helps to control the body's overall water
balance. ADH production is controlled
by the
h}spothalamus.
Various factors
can affect ADH production and thus dis-
turb the body's water balance, including
drinking alcohol, the disorder
diabetes
insipidus,
or a major operation.
ADHD The abbreviation for
attention
deficit h}speractivity disorder.
adhesion The joining of normally uncon-
nected body parts by bands of fibrous
tissue. Adhesions are sometimes pre-
sent from birth, but they most often
develop as a result of scarring after
inflammation. Adhesions are most com-
mon in the abdomen, where they often
form after
peritonitis
(inflammation of
the abdominal lining) or surgery. Some-
times, loops of intestine are bound
together by adhesions, causing intesti-
nal obstruction (see
intestine, obstruction
of).
In such cases, surgery is usually
required to cut the bands of tissue,
adipose
tissue A layer of fat just
beneath the skin and around various
internal organs. Adipose tissue is built
up from fat deposited as a result of
excess food intake, thus acting as an
energy store; excessive amounts of adi-
pose tissue produce
obesity.
The tissue
insulates against loss of body heat and
helps absorb shock in areas subject to
sudden or frequent pressure, such as
the buttocks of feet.
In men, superficial adipose tissue accu-
mulates around the shoulders, waist,
12
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