Bladder Flashcards
What is the trigone?
Smooth triangular region formed by ureteral orifices and urethral orifice. Stretch sensors here
What are the 4 surfaces of the bladder?
Posterior
Superior
Inferolateral x2
What cell types are found in the bladder lining?
Transitional epithelium lining (urothelium), also found in ureters
Detrusor muscle in wall
What prevents urine reflux during micturition?
Vesico ureteric valve, thickening of detrusor muscle
What is reflux nephropathy?
Incompetent vesico ureteric valve allows reflux of urine
Dilated ureter
Irregular renal outline, clubbed calyces, cortical scars
What is bladder support derived from?
Pelvic floor, perineal membrane & ligaments
Pubo-vesical ligament (female) - attach to pubic bone
Levator ani in both sexes - moves up when contracted
Pubo-prostatic ligament (male)
Where does blood supply to the pelvic viscera originate from?
Internal iliac artery
Bladder - vesical arteries
Describe venous drainage from pelvic viscera
Vesical & prostatic plexus to internal iliac vein
Describe lymph drainage from the pelvic viscera
External & internal iliac nodes
Sacral nodes
Umbilical region - follow urachus
What is an alternative to catheterisation if it is not possible?
Supra pubic catheterisation
Doesn’t enter peritoneal cavity
Where is the reflex micturition centre?
Sacral spinal cord
How do autonomic nerves travel to pelvic organs?
Nerve plexus on posterolateral wall of pelvic cavity (inferior hypogastric)
What reinforces micturition?
Abdo wall muscles and valsava manoeuvre
What effect does parasympathetic activity have on the bladder?
Detrusor muscle contraction
Internal urethral sphincter relaxation
What voluntary control do we have over micturition?
Pudendal nerve contracts external urethral sphincter
Need to relax to urinate
What control does sympathetic activity have on the bladder?
Contract internal urethral sphincter (ejaculation and stage fright)
Detrusor muscle relaxation
Why are females more prone to incontinence?
Shorter urethra
No protection from prostate
Sphincters can be damaged from childbirth
What sphincters do females have?
Internal urethral sphincter
External urethral sphincter
Compressor urethrae
Sphincter urethrovaginalis
What sphincters do males have?
Internal urethral sphincter
External urethral sphincter
Compressor urethrae
What is micturition?
Conversion of the continuous involuntary production of urine into the intermittent, consciously controlled voiding of urine
Autonomic reflex under voluntary control
Bladder expands with little change in pressure (filling time), but after certain volume get increase in intravesical pressure
Urge to micturate (micturition reflex)
What is the function of the bladder?
Collection and low pressure storage of urine
Expansion without leaks or reflux to kidneys
No significant increase in pressure until full
Appropriate expulsion of urine
Describe bladder structure
Hollow, muscular organ
Outer connective tissue layer (Adventitia)
Lining is transitional cell epithelium (urothelium)
Specialised, multi-layered, remains intact as bladder expands
Inside appears yellow with rugae (folds), except trigone region
Describe the layers of the bladder wall
Inside: transitional cell epithelium
Lamina propria
Detrusor muscle (smooth muscle) (muscularis propria)
Outside: Adventia (connective tissue)
What is detrusor muscle?
Bands of interlaced smooth muscle with gap junctions – acts as one
Describe the structure of the Bladder neck/ posterior urethra
2-3 cm long detrusor muscle +elastic tissue
How do we prevent leakage and reflux to the kidney?
Vesicourethral angle: urethra passes through pelvic floor muscle at an angle from the bladder. Well toned floor maintains the angle
Sphincters: internal sphincter-detrusor muscle and elastic fibres, involuntary control (bladder neck); external sphincter, skeletal muscle, voluntary control
Angle ureters enter the bladder: Ureters enter at uppermost angles of
trigone, Enter obliquely through the detrusor and pass 1-2 cm beneath the bladder mucosa before emptying into the bladder
What is the capacity of the bladder? And when is the 1st urge to micturate noticed?
Bladder capacity 300-500ml
1st urge 150-300ml
Every 3-4 hours
Why do females have a faster urine flow rate?
Female: Max flow 40-50ml/s, weaker bladder neck/ sphincter
Male: Max flow 30-40ml/s, require more pressure as urethra is longer
What happens during voiding of urine from the bladder?
Co-ordinated relaxation of internal sphincter & contraction of detrusor
Relaxation of external sphincter
Urethral relaxation, detrusor contraction, relaxation of sphincters, relaxation of pelvic floor muscles, funnelling of the bladder neck
What Sacral response and conscious control is there to voiding in adults and children?
Children – spinal reflex, no control – nappies
Adults – learn to control external sphincter until want to urinate, higher centre stimulation of pudendal nerve, keeps external sphincter shut
What nervous innervation controls bladder function?
Sympathetic - T10-L2 Relax bladder wall and contract int. sphincter Pudendal S2-S4 keeps the piss off the floor (external spincter)
Describe the sympathetic involvement in storage of urine
Sympathetic nervous system predominates
alpha-adrenergic receptors at base/neck of bladder increase muscle tone
Beta-adrenergic receptors in body of bladder decrease detrusor muscle tone
Properties pharmacologically manipulated using anti-adrenergic drugs
Describe the micturition reflex
Stretch receptors detect bladder filling
Parasympathetic neurons fire, smooth muscle (detrusor) contracts
Decreased sympathetic firing, internal sphincter relaxes
Decreased somatic motor neuron activity, external sphincter relaxes
Where does conscious control of the bladder come from?
Stretch receptors as normal but also relay message to pontine storage centre which acts via pudendal nerve, sympathetic activity and decreased parasymp activity to contract external sphincter and prevent urination until an appropriate time
Describe the micturition reflex when it includes conscious control
Stretch receptors to afferent nerves to pons
Pontine micturition centre activated
Sends impulse to pelvic splanchnic nerves and decreases activity of pudendal nerve and sympathetic nerves so relaxes sphincters
What ganglion to sympathetic neurons to the bladder act via?
Inferior hypogastric ganglion
What are potential sites for damage to the micturition pathway?
Cerebral lesion: involuntary co-ordinated micturition (stroke, PD, dementia)
Spinal shock: involuntary, uncoordinated, detrusor hyperflexia, (trauma, MS, spina bifida, compression by tumour)
Peripheral nerve lesion: atonic bladder (pelvic surgery, diabetesmellitus)
What are storage lower urinary tract syndromes?
Incontinence, frequency, urgency, nocturia
What are voiding lower urinary tract symptoms?
Poor stream, hesitancy, dysuria, intermittency, double voiding, terminal dribbling, retention
What is transurethral resection of prostate (TURP)?
Surgery cutting away a section of prostate
Used to treat benign prostate hyperplasia
Can lead to retrograde ejaculation and urinary incontinence
What is incontinence? And what sort of problems does it cause?
Unintentionally passing urine (or faeces) because of loss of control of bladder (or bowel) Constitutes a social and health problem Incontinence rarely shortens lives but huge effect on Quality of Life Most patients (cost) effectively treated at low risk
What are age related problems with incontinence?
Sphincter muscles lose tone – less effective at voluntarily retaining urine
Stroke, Alzheimer’s, other CNS problems affect cerebral cortex or hypothalamus so higher control of continence affected
In males, prostate enlargement causing retention
What are 5 types of incontinence?
FOCUS
Functional, overflow, continuous, urge, stress
How can incontinence be investigated and managed?
History: quantify symptoms, importance to patient, charts, questionnaires
Examination: Abdomen, pelvic (genitalia), digital rectum exam
Management: Lifestyle/training, Drugs, surgery
What are Urodynamics? And what can you measure with it?
Study of pressure and flow during storage, transport and expulsion of urine in the urinary tract (normally lower urinary tract)
Urine flow rate, residual urine, detrusor function measured at inflow and outflow cystometry
What is Outflow cystoscopy?
Catheter through urethra into bladder, transducer in the rectum
Fill bladder with fluid and pressures recorded in bladder and rectum
Bladder pressure is combined abdominal and detrusor pressure
Rectal pressure is from abdomen, Bladder – rectum = detrusor
What cell types are found in the bladder?
Transitional epithelium
Thick muscle layer
What cell types are in the urethra?
Transitional epithelium
Then squamous nearer exit point
What does the bladder develop from?
Anterior part of the cloaca with the allantois attached
What is the allantois?
Passes from cloaca to umbilicus in development
What problems can be caused by remnants of the allantois?
Urachal fistula - urine can leak out of umbilicus
Urachal cyst - lump at umbilicus
Urachal sinus - discharge cheesy smelly into umbilicus
What nerves carry sensation above and below the pelvic pain line from the bladder?
T12-L2 travel with sympathetics. Above
S2-S4 travel with parasympathetics. Below
What effect does the pudendal nerve have on the bladder?
Somatic = Stop (S2-4 pudendal nerve)
Contracts external urethral sphincter
Need to relax to urinate
What effect does sympathetic stimulation have on the bladder?
Sympathetic = Stop (L1-2)
Contracts internal urethral sphincter (ejaculation & stage fright)
Detrusor muscle relaxation
What effect does parasympathetic stimulation have on the bladder?
Parasympathetic activity (S2,3,4) = Pee
Detrusor muscle contraction
Internal urethral sphincter relaxation
