Urinary Bladder Structure

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The Urinary Bladder Structure: (Appendix 1) The urinary bladder collects and stores urine excreted by the kidneys, which passes through the ureters into the bladder. It is a hollow, distensible, muscular organ which is roughly pear shaped but becomes more balloon shaped as it fills with urine. When empty, it collapses and the inner wall develops folds called rugae, which gradually disappear as it fills, becoming more spherical. It consists of three layers, outer layer, middle layer and inner mucosa. 1,2 Outer layer: made up of loose connective tissue, containing nerves, blood and lymphatic vessels. On the posterior and inferior surfaces is the adventitia, a layer of areolar connective tissue that is continuous with that of the ureters.…show more content…
As the bladder fills with urine, pressure rises and the openings of the ureters are compressed, occluding the openings. This prevents backflow of urine into the ureters as the bladder fills and empties. Around the opening to the urethra, the circular smooth muscle fibres from the middle layer, form the internal urethral sphincter, controlling the outflow of urine from the bladder. This sphincter is not under voluntary control. Inferior to this is the external urethral sphincter, composed of skeletal muscle and is under voluntary control. This voluntary bladder control is learned in childhood. These three openings form the trigone, a triangular shaped area of smooth mucosa, closely bound to the muscular part of the bladder wall and very sensitive to…show more content…
When full, it extends into the abdominal cavity. The apex of the bladder is connected to the umbilicus by the median umbilical ligament, and anchored to the umbilicus by the right and left umbilical ligaments which are remnants of the umbilical arteries. The lowest part, the neck is attached to the pelvic diaphragm, where the bladder opens in to the urethra. It lies posteriorly to the uterus in females and posteriorly to the rectum in males.6 Anatomical relations of the urinary bladder are outlined below: Anatomical Relations of the Urinary Bladder (Female):  Anteriorly: the symphysis pubis  Posteriorly: the uterus and upper part of the vagina  Superiorly: the small intestine  Inferiorly: the urethra and the muscles of the pelvic floor 1 Anatomical Relations of the Urinary Bladder (Male):  Anteriorly: the symphysis pubis  Posteriorly: the rectum and seminal vesicles  Superiorly: the small intestine  Inferiorly: the urethra and prostate gland 1 Bladder Outflow

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