BLADDER, URINARY (probably akin to the verb to Now). A bag which receives the urine in man and animals after it is secreted by the kidneys. The bladder-wall consists of three eoats—a lining mucous membrane, a middle mus cular coat, and an outer coat which is serous, where the organ is covered over by peritoneum and fibrous throughout the rest of its extent. The mucous membrane of the bladder is lined with stratified squamons epithelium (see EPI THELIUM), and contains small racetno«e glands (see GLAND) }Ind lymph-nodules. The muscle of the middle coat is of the involuntary type and consists of inner and outer layers which are lon gitudinal, and a middle circular layer. The serous coat consists of a eonnective-tissue layer covered by a layer of flat endothelial cells. Where the serous coat is wanting. a fibrous layer covers the museular coat and blends with the surrounding connective tissue.
The average capacity of the bladder is one pint. The shape of the bladder is somewhat conical, the apex being upward, and the anterior part of the base constricted at the commencement of the urethra, forming the neck of the bladder. On each side, rather below its middle, open the two ducts from the kidneys (the ureters); an imaginary line drawn between them, and from each end of this line others drawn to the neck of the bladder, form au equilateral triangle. In this space, which is called the trigonum, the mucous membrane is not thrown into folds. but is smooth and very sensitive: the slightest pres sure upon it gives ris* to a desire for mieturi tion. Children's habits of emptying their blad ders when sleeping on their hacks are supposed to be (Inc to the urine accumulating in this part, as is also the distressing pain of stone. The bladder is situated in the pelvis, in adults. behind the pubes. in front of the rectum in the male and the uterus in the female, but much higher in the young. it is kept in position by four true or membranous ligaments, and false ligaments formed of folds of the peritoneum. In the male in front of the neck of the bladder lies the pros tate gland, surrounding the first part of the ure thra (q.v.). Like all cavities lined by mucous membrane. the bladder is subject to catarrhal inflammation, accompanied by an increased se eretion of mucus. with fermentation. render ing the urine turbid. causing a frequent and painful desire to mieturate, and constitutional disturbances. The symptoms may be relieved by
hot applications, along with opiates, antacids, and diuretics. if there is much mucus or blood or decomposed urine in the bladder, it may be washed out with a solution of boric acid, or of ereolin, or a weak mineral acid, in some eases. If there is any known cause for this intlanuna don. as a stone. it must be removed.
Some persons are frequently troubled with a desire to pass water; and many in this condition never effectually empty their irritable bladders, always leaving a portion which keeps up the irritation. This eondit ion frequently arises from the habit of retaining the urine so long as to over-distend and weaken the muscular walls of the bladder; but it may he induced by general debility, the irritation of worms. cold. or an irri tating state of the wine itself, or by nervousness. as in candidates for examination, etc. The lie4t, treatment is tonics. and soothing the irritability with sedatives. When this irritability is noc turnal. it may be from the patient lying on the back, as explained above; it generally occurs in delicate children, and is more a habit than a disease.
Paralysis of the bladder may be the result of accident, or disease of the nervous centres, or over-distention. In this condition the urine ac cumulates and dribbles away, and must be drawn off by the catheter (q.v.). This dribbling, or in continence, must be distinguished from irritable bladder, as it is in nearly every ease the sign of a distended bladder. Retention of the urine may be caused by mechanical obstacles to its exit, by paralysis, or by an absence of volitional power over the muscles. This last is termed hysterical retention, and is common in young girls, in per sons suffering from seasickness. from nostalgia. from operation or from accident, such as a broken leg. etc. The power generally soon re turns. Any long-eontinued difficulty in passing water is generally followed by a thickening of the walls of the bladder itself, or hypertrophy. The mucous membrane may form pouches in these thickened walls—a condition which is called sac ciliated bladder: cancerous diseases and tuberele may also attack this organ.
The bladder is liable to be ruptured by acci dent from without: as, for instance. by a blow. As this accident is usually fatal, prompt surgical aid must be secured.