Bma Illustrated Medical Dictionary

bladderThe hollow, muscular organ in
the lower abdomen that acts as a reser-
voir for urine. It lies within, and is
protected by, the pelvis. An adult blad-
der can hold about 0.5 litres of urine
before the need to pass urine is felt.
The bladder walls consist of muscle
and an inner lining. Two ureters carry
urine to the bladder from the kidneys.
At the lowest point of the bladder is the
opening into the urethra, which is known
as the bladder neck. This is normally
kept tightly closed by a ring of muscle
(the urethral sphincter). The function of
the bladder is to collect and store urine
until it can be expelled. Defective blad-
der function, leading to problems such
as incontinenceand urinary retention,
can have a variety of causes. (See also
bladder,disorders of; enuresis).
bladder cancerSee bladder tumours.
bladder, disorders ofA group of dis-
orders affecting the bladder, including
inflammation (cystitis) usually caused
by a bacterial infection; calculi(stones);
impairment of the nerve supply; and
tumours. In men, obstruction to urine
flow from the bladder by an enlarged
prostate gland may cause urinary reten-
tion. Tumours of, or injury to, the spinal
cord may affect the nerves controlling
the bladder, leading either to retention
or incontinence. Bladder stones are
caused by the precipitation of substan-
ces that are present in the urine. Injury
to the bladder is uncommon but may
occur if the pelvis is fractured when the
bladder is full.

Disturbed bladder control can also

result from nerve degeneration in condi-

tions such as diabetes mellitus, multiple

sclerosis, or dementia. An unstable or

irritable bladderis a common condition

and is sometimes associated with a uri-

nary tract infectionor prolapse of the

uterus. Tension or anxiety can cause fre-

quent urination. In children, delayed

bladder control (see enuresis) most

often results from delayed maturation

of the nervous system.

bladder tumoursGrowths originating

in the inner lining of the bladder. Many

are papillomas(small wart-like growths),

which tend to recur and will eventually

become cancerous. Other, more malig-

nant, growths may extend not only into

the bladder cavity but may also spread

through the bladder wall to involve

nearby organs such as the colon, rec-

tum, prostate gland, or uterus.

Bladder cancer is more common in

smokers and workers in the dye and

rubber industries. Haematuria(blood in

the urine) is the main symptom of blad-

der cancer. A tumour may obstruct the

entry of a ureter into the bladder, caus-

ing back pressure and pain in the

kidney region, or may obstruct the ure-

thral exit, causing difficulty in passing,

or retention of, urine.

Bladder tumours are diagnosed using

cystoscopyand biopsy of the abnormal

area. If small, they can be treated by

heat or surgically during cystoscopy.

They tend to recur at the same or other

sites within the bladder, so that regular

BLADDER BLADDER TUMOURS

B

BLADDER

Bladder

Vagina

Ureter

Rectum

Uterus Rectum

FEMALE MALE

Bladder

Penis

Pelvic

cartilage

Urethra

Ureter

Prostate

gland

Scrotum

Urethra

Pelvic
cartilage