Normal physiology and pathophysiology of the lower urinary tract

Table of Contents

1. Introduction
2. Bladder Filling
3. Voiding
4. Pathophysiology of micturition
5. Impact of bladder symptoms and urinary incontinence
6. Summary
7. References

Introduction

This learning activity looks at the normal neurobiological control of bladder filling and emptying, the causes of urinary incontinence and the impact of urinary incontinence on the quality of life of individuals, families and carers.

In the activity you will:

- Understand the normal neurobiological control of bladder filling and emptying.

- Critically discuss the aetiology of urinary incontinence

- Evaluate the impact of urinary incontinence on the quality of life of individuals, families and carers

The lower urinary tract (LUT) is innervated by parasympathetic sacral nerves (S2-S4), which cause contraction of the bladder muscle (detrusor) and relaxation of the urethra, and lumbar sympathetic nerves (T10-L2), which cause relaxation of the bladder body and contraction of the bladder neck and urethra. Pudendal nerves also contribute to continence by controlling the external urethral sphincter and associated mechanisms of the pelvic floor.

All these nerves contain sensory as well as motor pathways. The brain exerts hierarchical control over the peripheral innervation of the bladder, which is co-ordinated by micturition centres in the pons, within the brain stem, and the frontal lobe (Fowler, 1999).