Introduction to Micturition Clinical Science Team

Objectives Differentiate between the gross anatomical features of the male and female urinary tracts Briefly describe the structure and function of the ureters Describe the gross structure, layers, nerve supply and function of the urinary bladder Describe the structure and function of the urethra and urethral sphincters Briefly explain the process of micturition

Gross Anatomy of the Urinary Tract Male Female

Gross Anatomy of the Urinary Tract Male

Gross Anatomy of the Urinary Tract Female What structure is superior to the bladder in this diagram? What structure is anterior to the bladder? What structure is posterior to the urethra?

The Ureters Function of the ureters is to convey urine from the kidney to the urinary bladder. The angle that the ureters pass through the bladder wall prevents reflux of urine from the bladder).

The Urinary Bladder

Transitional Epithelium Lining of the Urinary Bladder

The Urinary Bladder Is a spherical hollow sac Consists of three layers: Inner mucosa, composed of transitional epithelium Middle layer of involuntary detrusor muscle Outer layer of loose connective tissue Function: Reservoir for urine Evacuation of urine (under control of ANS)

The Male Urethra

The Male and Female Urethra Male Urethra: Female Urethra: cm long 3-5 cm long Tortuous in configuration Straight in configuration Composed of three parts (see previous diagram)

The Female Urethra

Structure of the Urethra What is different about transitional epithelial tissue?

Structure of the Urethra Layers: Essentially the same as the remainder of the urinary tract Lined with mucous membrane Function: Conveys urine from the bladder to the exterior

Questions What gland lies next to the urinary bladder in men? How is the male urethra different to the female urethra? What membrane covers the superior aspect of the bladder?

Questions What is the name of the triangular area between the entry point of the two ureters and the internal urethral orifice? What are the ‘pelvic floor muscles’ and what do they have to do with micturition?

Urethral Sphincters The Internal Sphincter: Forms part of the bladder neck outlet Composed of circular smooth muscle (involuntary) Is under the control of the ANS

Urethral Sphincters The External Sphincter: Forms part of the pelvic floor muscles Composed of circular striated muscle (voluntary) Is under the control of the somatic nervous system

Involuntary (Autonomic) Control of Micturition Bladder Detrusor Muscle Stretch Receptor Sensory Neurone Parasympathetic Motor Neurone (contracts Detrusor muscle & opens internal sphincter) Internal urethral sphincter Spinal Cord

Voluntary Control of Micturition Pons Sensory Cortex Motor Cortex External Urethral Sphincter Voluntary (Somatic) Pudendal Nerve: Controls opening & closure of external sphincter

Questions What sort of muscle is contained in the wall of the ureter (and bladder)? What sort of pain is experienced when the ureters are inflamed? What is the maximum volume of urine that the adult bladder can hold comfortably?

Questions How much urine (normal range) is produced daily in an adult? What is the minimum amount of urine that should be produced per hour in an adult What structure does the urethra pass through? Why is glucose an abnormal constituent of urine?

Micturition animation Please watch the following short animation,animation, it summaries the micturition reflex nicely 1anim0081.exe

Conclusion In this session we have: 1.Discussed the anatomical features of male and female urinary tracts 2.Discussed the structure, function, layers, and nerve supply of the bladder and the urethra 3.Illustrated the control of micturition

Maintaining Continence What knowledge and skills are needed by the nurse in relation to maintenance of continence in patients?