Name these parts of the urinary bladder
Distal sphincter mechanism is composed of which structures?
- Urethral smooth muscle
- Intrinsic rhabdosphincter
- Peri-urethral musculature
Which muscle undergoes relaxation during the storage phase of micturition?
Detrusor
What is the normal capacity of the urinary bladder?
400-500mL
What are the layers of the detrusor muscle
Longitudinal - Innermost layer
Circular - middle layer
Longitudinal - outermost layer
Name these layers of the urinary bladder
The vasculature of the bladder is primarily derived from the ___ vessels.
The vasculature of the bladder is primarily derived from the internal iliac vessels.
Describe the blood supply to the urinary bladder
Arterial supply is via the superior vesical branch of the internal iliac artery.
In males, this is supplemented by the inferior vesical artery, and in females by the vaginal arteries.
In both sexes, the obturator and inferior gluteal arteries may also contribute small branches.
Describe the venous drainage of the urinary bladder
Vesical venous plexus, which empties into the internal iliac veins.
Describe the parasympathetic innervation of the bladder
P for Pee
Parasympathetic fibres are for peeing.
Parasympathetic fibres are derived from pelvic splanchnic nerves (S2-4)
Motor to detrusor and inhibitory to internal sphincter
Describe the sympathetic innervation of the urinary bladder
S- for storage
Sympathetic fibres are for storaging- bladder filling
Derived from T11-L2
Relaxes detrusor and contracts internal sphincter
The ____ fibres are for peeing?
A) Sympathetic
B) Parasympathetic
B) Parasympathetic
P for Peeing
The ____ fibres are for bladder storage?
A) Sympathetic
B) Parasympathetic
A) Sympathetic
S for Storage
Name the sphincters for the urinary bladder
- Internal urethral sphincter
- External urethral sphincter
What is the epithelium of the urinary bladder
Transitional
What happens to the detrusor muscle during micturition
The detrusor muscle is able to contract during micturition to expel the urine.
Describe the internal urethral sphincter
- Male – consists of circular smooth fibres, which are under autonomic control.
- Females – functional sphincter (i.e. no sphincteric muscle present).
Describe the external urethral sphincter
- It is skeletal muscle, and under voluntary control.
- Supplied by the pudental nerve (somatic motor fibre)
Parasympathetic innervates the internal urethral sphincter to ____ and causes the _____ of the detrusor muscle. Overall, causing ____.
A) Relax
B) Contracts
C) Urination
Sympathetic innervates the internal urethral sphincter to ____ and causes the _____ of the detrusor muscle. Overall, causing ____.
A) Contract
B) Relaxation
C) Bladder storage
Sympathetic fibres that innervate the urinary bladder is the ____ nerve, that comes from the _____ spinal cord level.
A) Hypogastric
B) T11 - L2
What are the 2 main populations of receptors in the urinary bladder
Cholinergic (muscarinic) and adrenergic
Describe the Cholinergic (muscarinic) receptors of the urinary bladder
- Muscarinic subtypes M1-M3 in bladder smooth muscle
- M2 80% population, but M3 functionally MOST important – mediates bladder contraction
Describe the adrenergic receptors of the urinary bladder
Adrenergic subtypes β1 and β2
Which muscarinic receptor of the bladder cause the bladder contraction.
M3
What are the 3 layers of the wall of the bladder body
adventitia, smooth muscle, and urothelium.
Whcih adrenergic receptor of the bladder mediated detrusor relaxation (weakening) during storage phase
β-3 adrenoceptor
What are the 3 types of neurological lesions that can affect bladder function
- Suprasacral lesions - lesion at the T11 level.
- Infrasacral lesions - L1 level.
- Suprapontine- lesion above the pons
Describe suprapontine lesions
Overactive bladder with intact sphincter behaviour
Detrusor is contracting too much. Gives you symptoms of urgency. Kidney is safe as when they want to pee they can.
What are the common causes of suprapontine lesions
- Dementia
- Parkinson’s disease
- Relative dopamine deficiency
Describe suprasacral lesions
When the pee they cannot completely empty the bladder. Build up of pressure that eventually goes into the kidneys
What is the most common cause of suprasacral lesions
Multiple sclerosis (MS)
Describe infrasacral lesions
Result in detrusor underactivity and voiding dysfunction
Present with interrupted stream and a feeling of incomplete emptying
What are the common causes of infrasacral lesions
Sacral cord injury
Lumbar disc herniation
Cauda equina
Define Obstructive nephropathy
Damage to renal parenchyma resulting from obstruction to flow of urine
Describe high pressure chronic retention (HPCR)
- Tense painless bladder
- Maintenance of micturition
- Renal impairment
- Always at least 800mls of urine left in the bladder- even after emptying
Define nocturnal enuresis
Involuntary urination that happens at night while sleeping
Describe the 3 stage theory of prostatism
- Prostatic hypertrophy causes increasing outlet resistance causes bladder muscle hypertrophy- trabeculation
- As this progresses sacculation and diverticulum formation occurs and ureters dilate
- Bladder becomes decompensated – flaccid, large and over distended NB overflow incontinence