Urinary tract and urination
Urinary tract in human body consists of a bladder, a urethra, two kidneys and two ureters. Kidney filters the human blood and the waste and extra water produced after the filtration process is the urine. Urine passes down the kidneys through two ureters and is collected in the bladder which is the store house of urine. Bladder enlarges in round shape when urine is filled in it and shrinks when it is emptied. Bladder is situated in the pelvis attached to muscles, pelvic bones and other organs. A tube called urethra connects bladder to the outside world and through this urethra the urine is passed out.
Bladder muscles and sphincter muscles near the opening of the bladder to the urethra, controls the process of urination. A normal healthy bladder can contain 16 ounces of urine up to 2 to 5 hours. The sphincter muscles near the opening of the bladder to the urethra acts like rubber bands and keep the sphincter muscles tightly closed so that no urine leaks out of the bladder. When the brain decides to urinate sensing that the bladder is full it sends signals to bladder muscles which lightens and squeezes urine out of it. At the same the sphincter muscles open and urine flows out of the bladder through urethra. When brain sends necessary signals in the correct sequence natural urination takes place.
Urodynamic tests are intended to understand how far the bladder muscles, sphincter muscles and urethra are successful in storing and releasing the urine as desired by the patient. It can also reveal whether the bladder contributes to leakage of urine though the involuntary contractions of its muscles, whether the sphincter muscles are working properly etc.
Urodynamic testing can be as simple as observing the urination process and recording the details like delay in starting urination, the volume of urine produced, the ability to stop urination in mid stream etc. Urodynamic testing also make use of sophisticated instruments with the help of which the pictures of bladder filling and emptying, the pressure inside the bladder, recording of the muscle and nerve activity etc are accomplished. The cause and type of problems in the lower urinary tract can be understood with the help of Urodynamics. Depending upon the test to be conducted the patient may be requested to come with a full bladder for testing or with some other preparations like stopping the intake of certain medications and making some changes in the fluid intake.