7 Flashcards
(36 cards)
What is micturition?
Can be broken down as:
- urine is made in kidney
- urine is stored in bladder
- sphincter muscles relax
- bladder muscle (detrusor) contracts
- bladder is emptied through urethra and urine is removed from body
What are the functions of the nervous system in relation to the lower urinary tract?
- provide sensations of bladder filling and pain
- to allow bladder to relax and accommodate increasing volumes of urine
- to initiate and maintain voiding so that bladder empties completely, with MINIMAL residual volume
- to provide an integrated regulation of smooth muscle and skeletal muscle sphincters of the urethra
What is the Pontine micturition centre (PMC)?
-collection of neuronal cell bodies located in the rostral pons in the brainstem involved in the supraspinatous regulation of micturition
What are the two regions within the PMC?
L region and M region
What does L region do?
-has sympathetic fibres associated with storage and relaxation of the bladder and contraction of the EUS
What does M region do?
-has parasympathetic NS and involved in voiding
What is the periaqueductal gray (PAG)?
-acts as a relay station for ascending bladder info from spinal cord and incoming signals from higher brain areas
What does the M region do in regards to bladder filling and distension?
- helps to control the detrusor muscle of bladder and inhibitory inter neurons regulating onuf’s nucleus
- during bladder filling, neurons within M region are turned off
- but at a critical level of bladder distension, the afferent info will switch M region on and enhance activity
- activation results of relaxation of EUS and contraction of bladder
What are the two phases of the functional activity of the lower urinary tract?
- filling
- voiding
What is the filling phase?
- bladder relaxes and accommodates increasing volumes of urine (bladder filling)
- urethral sphincters increase their tone to maintain continence
- storage phase
- no detrusor contraction
What occurs in the voiding phase?
- urethral sphincters relax and bladder contracts
- bladder contraction is greater in men than women
- voluntary initiation
- complete emptying
What types of innervation does the bladder and its sphincters receive?
- sympathetic
- parasympathetic
- somatic
How does sympathetic innervation occur in the bladder?
- originates from neurons from T10 to L2
- preganglionic fibres pass through lumbar splanchnic nerves to superior hypogastric plexus where they give rise to left and right hypogastric nerves
- in the plexus, fibre synapse with postganglionic fibres
- postganglionic fibres go to bladder wall
How does parasympathetic innervation to the bladder occur?
- originates from S2-S4
- preganglionic fibres go to bladder via pelvic splanchnic nerve
- then synapse with postganglionic neurons in the body and neck of bladder
How does somatic innervation occur in the bladder?
- originates from motor neurons arising from S2-S4
- through the pudendal nerve these motor neurons innervate and control the voluntary skeletal muscle of EUS
How can i make sense of the innervation to bladder?
STUDY DIAGRAM
NOv 6 2019 note
What is urinary incontinence?
- non-fatal but socially disabling condition
- occurs when the bladder pressure is greater than the urethral sphincter pressure
- happens either when the detrusor pressure is high or the sphincter pressure is low
How is continence achieved?
- combined effect of smooth muscle of urethra, surrounding peri-urethral striated muscle and the elasticity of the connective tissue
- support of the urethra by the muscles and ligaments of the pelvic floor
What will happen to the bladder if you get a lower motor neurone lesion?
- low detrusor pressure
- large residual urine
- overflow incontinence
- S2, 3, 4 affected
- reduced perianal sensation
- lax anal tone
What will happen to the bladder in an upper motor neurone lesion?
- high pressure detrusor contractions
- poor coordination with sphincters
- detrusor sphincter dyssnergia
- thickened detrusor
- dilated ureters
What are the different types of incontinence?
Stress Urinary Incontinence (SUI)
-complaint of involuntary leakage on effort or exertion, or on sneezing or coughing
Urgency Urinary Incontinence (UUI)
-complaint of involuntary leakage (of urine) accompanied by or immediately proceeded by urgency
Mixed Urinary Incontinence (MUI)
-complaint of involuntary leakage (of urine) associated with urgency and also with exertion, effort, sneezing or coughing
Overflow Incontinence
What type of incontinence is the most common?
SUI
What are the risk factors for urinary incontinence?
O and G
- pregnancy and childbirth
- pelvic surgery
- pelvic prolapse
Promoting
- co-morbidities
- obesity
- age
- rise in intra-abd pressure
- cognitive impairment
- UTI
- drugs
- menopause
Predisposing
- race
- family predisposition
- anatomical abnormalities
- neurological abnormalities
- radiotherapy makes pelvis less compliant
What type of history and examination would you do for a pt. Suspected with UI?
History
-categories type of UI
Examination
- BMI
- abd exam to exclude palpable bladder
- digital rectal examination
- stress test for external genitalia
