Continence And Lower Urinary Tract Flashcards
Urine storage
Low pressure with perfect continence
Urine emptying
Periodic complete urine expulsion, at low pressure, when socially convenient
Motor nerves
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Sensory nerves
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Bladder filling
Sympathetic system is switched on
There are beta 2 and beta 3 receptors in the wall of the bladder and they’re activated to cause bladder relaxation
The hypogastric nerve also travels to the bladder neck and works on alpha receptors in that area
The alpha receptors are activating, this causes bladder neck contraction
At the same time the parasympathetic system is switched off and the M2, M3 receptors are not activated
At the same time the voluntary pudendal nerve is switched on and that causes tonic contraction of the striated external urethral sphincter
Bladder emptying
Sympathetic system is switched off causes relaxation of the bladder neck
Parasympathetic system is switched on, which causes a contraction of bladder wall through the M2 and M3 receptors and main neurotransmitters is ACh and the voluntary muscles are switched off with the pudendal nerve being switched off and the striated sphincter relaxes
Storage reflex/ bladder filling
1) Distention of the bladder produces low level bladder afferent firing
2) Triggers guarding reflex-
A- sympathetic outflow in the hypogastric nerve to bladder outlet/neck
The hypogastric nerve also travels to the bladder neck and works on alpha receptors in that area
The alpha receptors are activating, this causes bladder neck contraction
B- pudendal outflow to external urethral sphincter
At the same time the voluntary pudendal nerve is switched on and that causes tonic contraction of the striated external urethral sphincter
3) Sympathetic outflow also inhibits contraction of the detrusor muscle (muscle in wall of bladder)
There are beta 2 and beta 3 receptors in the wall of the bladder and they’re activated to cause bladder relaxation
A region in the Rostral pons pontine storage centre might increase striated urethral sphincter activity
Voiding reflex/ bladder emptying
1) Intense bladder-afferent firing in the pelvic nerve
2) Triggers spinobulbospinal reflex
A- afferent signalas passed to peraquedictal gray (PAG)
B- pontine micturition centre (PMC) activated
3) PMC ‘on/off’
A- Parasympathetic outflow to bladder and urethral smooth muscle (green)
B- inhibits the sympathetic and pudendal outflow to bladder outlet/neck so striated sphincter relaxes
Parasympathetic system is switched on, which causes a contraction of bladder wall through the M2 and M3 receptors and main neurotransmitters is ACh
Classification of lower urinary tract dysfunction
Failure to store or to void is due to bladder and outlet
Types of incontinence
Stress
Urgency
Mixed
Stress incontinence
Loss of urine with excretion or sneezing or coughing
Urgency incontinence
Leakage accompanied by or immediately preceded by urinary urgency
Mixed incontinence
Loss of urine associated with urgency and also with excretion, effort, sneezing or coughing
Overflow incontinence
Leakage of urine associated with urinary retention
Total incontinence
Is the complaint of leakage
Stress urinary incontinence theory 1
Urethral hyper mobility age/parturition weakness in pelvic floor muscle/ connective tissue
Weakened vaginal hammock
Impaired pressure transmission
Theory II
Intrinsic sphincter deficiency due to direct muscle Injury or nerve injury
Urgency urinary incontinence
Urgency is a sensory symptom
Urgency urinary incontinence is variably associated with detrusor over activity
Detrusor overactivity= non volitional detrusor contraction
Can be idiopathic or neurogenic
Total incontinence
Caused by a fistula between vagina and bladder (in this case)
Prolonged second stage of labour causes pressure on bladder wall which causes damage in urinary sphincter- so bad incontinence
Reversible causes of incontinence
D- delirium
I- infection
A- strophic vaginitis/urethritis
P- psychological
P- pharmacological (diuretics, narcotics)
E- endocrine/ excessive urinary output
R- restricted mobility
S- stool impaction
