Normal and Abnormal Function: An Overview

Abstract

The bladder (reservoir) and its outlet function as a pair of interrelated structures whose coordinated actions in the adult normally bring about (1) low-pressure reservoir filling and urine storage without involuntary leakage and (2) periodic voluntary emptying of the system, again at low pressure. The neuroanatomic, physiologic, and pharmacologic milieu which normally serves as a background and operating system for this simple sounding cycle is well described in the previous chapter. For conceptualization and a framework for evaluation, categorization, and management of abnormal function, it is logical to consider these two phases as relatively discrete: bladder filling and urine storage, and bladder emptying/voiding. This micturition cycle normally displays these two modes of operation in a simple on-off fashion which involves (1) activation of storage reflexes affecting the outlet and inhibiting the detrusor contraction reflex and (2) switching to inhibition of the storage reflexes and concomitant activation of the voiding reflex—and back again. As an easy to understand framework for subsequent discussion of evaluation, categorization, and management, the basics of these two phases are summarized followed by a brief description of what can and does malfunction.