Urinary bladder

The urinary bladder is a hollow muscular organ in humans and some other animals that collects and stores urine from the kidneys before disposal by urination. In the human the bladder is a hollow muscular, and distensible (or elastic) organ, that sits on the pelvic floor. Urine enters the bladder via the ureters and exits via the urethra. The typical human bladder will hold between 300 and 500 mL (10.14 and 16.91 fl oz) before the urge to empty occurs, but can hold considerably more.Vertical section of bladder wall.Layers of the urinary bladder wall and cross section of the detrusor muscle.Anatomy of the male bladder, showing transitional epithelium and part of the wall in a histological cut-out.Urinary bladder (black butterfly-like shape) and hyperplastic prostate (BPH) visualized by medical ultrasound. The urinary bladder is a hollow muscular organ in humans and some other animals that collects and stores urine from the kidneys before disposal by urination. In the human the bladder is a hollow muscular, and distensible (or elastic) organ, that sits on the pelvic floor. Urine enters the bladder via the ureters and exits via the urethra. The typical human bladder will hold between 300 and 500 mL (10.14 and 16.91 fl oz) before the urge to empty occurs, but can hold considerably more. In humans, the bladder is a hollow muscular organ situated at the base of the pelvis. Urine collects in the bladder, fed from the two ureters that connect the bladder with the kidneys. Urine leaves the bladder via the urethra, a single muscular tube ending in an opening – the urinary meatus, where it exits the body. Anatomists divide the bladder into:. The apex (prev.vertex) is directed forward toward the upper part of the pubic symphysis, and from there the median umbilical ligament continues upward on the back of the anterior abdominal wall to the umbilicus. The peritoneum is carried by it from the apex on to the abdominal wall to form the middle umbilical fold. The neck of the bladder is the area at the base of the trigone that surrounds the internal urethral orifice that leads to the urethra. In males the neck of the urinary bladder is adjacent to the prostate gland. The three openings, two ureteric orifices, and the internal urethral orifice mark the triangular area called the trigone of the bladder. These openings have mucosal flaps in front of them that act as valves in preventing the backflow of urine into the ureters, known as vesicoureteral reflux. Between the two ureteric openings is a raised area of tissue called the interureteric crest. This makes the upper boundary of the trigone. The trigone is a smooth-muscle area that forms the floor of the bladder above the urethra. It is an area of smooth tissue for the easy flow of urine into and from this part of the bladder - in contrast to the irregular surface formed by the rugae. In men, the prostate gland lies outside the opening for the urethra. The middle lobe of the prostate causes an elevation in the mucous membrane behind the internal urethral orifice called the uvula of urinary bladder. The uvula can enlarge when the prostate becomes enlarged. The bladder is situated below the peritoneal cavity near the pelvic floor and behind the pubic symphysis. In men, it lies in front of the rectum, separated by the recto-vesical pouch, and is supported by fibres of the levator ani and of the prostate gland. In women, it lies in front of the uterus, separated by the vesico-uterine pouch, and is supported by the elevator ani and the upper part of the vagina. The wall of the urinary bladder is normally 3–5 mm thick. When well distended, the wall is normally less than 3 mm. The inner walls have a series of ridges, thick mucosal folds known as rugae that allow for the expansion of the bladder.