BLADDER (urinary) is a bag formed of fibrous membrane externally, muscular fibers in the middle, and mucous membrane for an internal lining. The peritoneum (see ABDOMEN) covers its back. The shape of the B. is somewhat conical, the apex being upward., and the anterior part of the base constricted at the commencement of the ure thra, caled 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 include an equilateral triangle. In this space, which is called the trigone, the mucous membrane Is not thrown into folds, but is smooth and very sensitive, the slightest touch upon it giving rise to a desire for niicturition. The habit of some children to empty their bladders when sleep big on their backs, is supposed to be due to the urine accumulating in this part, as is also the distressing pain of stone.
The B. is situated in the pelvis in adults, 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. The neck of the B. is surrounded by the. prostate gland, and here the urethra (q.v.) begins. Like all cavities lined by mucous membrane, the B. is subject to catarrhal inflammations, which are accompanied by an increased secretion of mucus, rendering the urine turbid, frequent and painful desire to micturate, and very great con stitutional disturbance. The symptoms may be acute, and must be relieved by local and hot fomentations along with opiates; or they may be chronic, when some medicines, as the vca-ursi (see ARBUTUS), bucku (q.v.), the preparations of iron, and the mineral acids, are found useful. If there is much mucus, or decomposed urine in the B., it may be washed out with warm water, in which a minute quantity of nitric acid has been dropped. Of course, if there is any known cause for this inflammation, as a atone, it must be removed.
Irritable B. resembles the former disease, but is produced by various causes unac companied by inflammation. Some persons, from mere nervousness, are frequently
troubled with a desire to pass water; and strange as it may seem, many in this condition never effectually empty their bladders, always leaving a portion, which keeps up the irritation. This condition frequently arises from the habit of retaining the urine so long as to over-distend and weaken the muscular walls of the B.; but it may be induced by general debility, the irritation of worms, cold, or an irritating state of the urine itself. The best treatment is tonics, and soothing the irritability with sedatives. When this irritability is nocturnal, 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 B. may be the result of accident, or disease of the nervous centers, or over-distension; in this condition the urine accumulates and dribbles away, and must be drawn off by the catheter (q.v.). This dribbling, or incontinence, must be carefully distinguished from irritable B., as it is in nearly every case the sign of a distended bladder. 1?etention 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 kysterical retention, and is common in young girls, in persons suffering from sea-sickness, from being in a strange place, an accident, such as a broken leg, etc. If the affection is not encouraged by an ollicious use of the catheter, the power generally soon returns. Any long-continued difficulty in passing water is generally followed by a thickening of the walls of the B. itself, or hypertrophy. The mucous membrane may form pouches in these thickened walls, which is called sacculated B., and'cancerous diseases, and tubercle, may also attack this organ.
The B. is liable to be ruptured by accident from without, as, for instance, by a blow or hurt from a saddle; and as this accident is usually fatal, it cannot be too carefully guarded against. If the B. is ruptured posteriorly, the accident is always fatal.