Urinary System Care nd Maintenance In Neurologically Impaired Dogs nd Cats

摘要

The voluntary and involuntary control of urination is called micturition. This process is a regulated by a complex series of pathways in the central and peripheral nervous systems. In the normal adult canine or feline patient there are two phases of micturition, the filling and emptying phases. During the filling phase signals from stretch receptors in the bladder are sent along afferent (sensory) nerves to the spinal cord and then on to the brain with information that the bladder is filling with urine. If it is an inappropriate time or place to urinate signals are sent to the bladder to loosen the bladder wall muscles to allow for more urine to enter. Signals are also sent along efferent (motor) neurons to the pelvic floor muscles to contract as well as to the internal and external pseudo-sphincters of the urethra to continue to contract to prevent voiding of urine. As the bladder fills, signals continue to travel to the brain advising the brain that the bladder is nearly full and urination shouldcommence. Once a suitable place or time for urination is found, or if the bladder becomes too distended, the emptying phase of micturition commences. During the emptying phase, signals from the brain travel to the detrusor muscle of the bladder to signal it to contract. At the same time inhibitory signals are sent to the internal and external urethral sphincters allowing them to relax. This synergistic effort allows urine to flow from the body. Once the bladder is empty the filling phase begins again as the muscles of the pelvic floor and urethra contract once more.