Urinary bladder




The urinary bladder, or simply bladder, is a hollow muscular organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In the human the bladder is a hollow muscular, and distensible 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.

The Latin phrase for "urinary bladder" is vesica urinaria, and the term vesical or prefix vesico - appear in connection with associated structures such as vesical veins. The modern Latin word for "bladder" – cystis – appears in associated terms such as cystitis (inflammation of the bladder).

Comments

Post a Comment

Popular posts from this blog

Structure

Image
In humans, the bladder is a hollow muscular organ situated at the base of the pelvis. In gross anatomy, the bladder can be divided into a broad fundus, a body, an apex, and a neck. The apex 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 next to the prostate gland. The bladder has three openings. The two ureters enter the bladder at ureteric orifices, and the urethra enters at the trigone of the bladder. These ureteric 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. B
Read more

Function

Image
Urine, excreted by the kidneys, collects in the bladder because of drainage from two ureters, before disposal by urination (micturition). Urine leaves the bladder via the urethra, a single muscular tube ending in an opening called the urinary meatus, where it exits the body. Urination involves coordinated muscle changes involving a reflex based in the spine, with higher inputs from the brain. During urination, the detrusor muscle contracts, and the external urinary sphincter and muscles of the perineum relax, allowing urine to pass through the urethra and out of the body. The urge to pass urine stems from stretch receptors that activate when between 300 - 400 mL urine is held within the bladder. As urine accumulates, the rugae flatten and the wall of the bladder thins as it stretches, allowing the bladder to store larger amounts of urine without a significant rise in internal pressure. Urination is controlled by the pontine micturition center in the brainstem. Stretch receptors in the
Read more