The anterior surface, in the collapsed state of the organ, lies behind the symphysis pubis, with which it is by loose cellular tissue; when distended, the bladder rises, and its anterior surface comes in relation, or in contact, with the recti muscles of the abdomen. The posterior surface is covered by the peritoneum, which in the male is reflected upon it from the rectum, in the female from the uterus and vagina ; it is then reflected from the sides of the bladder to the iliac foam; nt the points of reflection it forma folds, one on each side and two posteriorly; these have been improperly described as ligaments, for instead of confining the bladder they serve rather as provisions to facilitate its expansion.
The lateral regions are partially covered by the peritonwuni ; running along them we find the umbilical arteries, or their remains, in both sexes, and the rasa deferentia in the male. The superior region, or funding, is partially covered by the peritoneum, which is reflected thence on to the inner surface of the recti lunacies ; it has a fibrous cord attached to it termed the urachus, which lies between the peritonwum and the recti muscles, and being accompanied by the remains of the umbilical arteries extends; to the umbilicus, where it becomes Identified with the abdominal nponeuromes. Tide fibrous; cord appears to be useful In retaining the bladder In its situation, for never in the human subject, except in certain cases of malformation, which are very rare, does it present the form of a canal, such as it is found to be in the young of certain quadrupeds, in which it is the medium of eniainunication between the bladder and a bag, or sac termed the allantohL The secretion of the urine is performed by the kidneys [Kinser] ; it is constantly going on, and does not exhibit those alternations of action and repose observable in the other secretions.
The urine, being accreted, dribbles along the ureters, and its descent is probably sided by the contractility of these tubes and the impulse of the neighbouring arteries. It drops into the bladder and gradually distends it, but it is prevented from regurgitating into the ureters in consequence of these tubes taking au oblique course between the muscular and mucous coats before they perforate the latter. As the urine accumulates, these tubes are more and more compressed, and the obstacle to regurgitation is increased ; but the column of urine descending along the ureters, being higher than that contained in the bladder, is not prevented from entering into it.
When a sufficient quantity of urine is accnmulated in the bladder, varying according to the degree of irritability of the organ, a general uneasy sensation is produced, and a more particular one referred to the trigone vcsicale : the diaphragm and abdominal muscles are called into action, the resistance of the neck of the bladder is overcome (the sphincter, if we admit its existence, relaxes), tho muscular fibres of the bladder contract, and are able without further assistance to evacuate every drop of its contents.