The Lower Urinary Tract Flashcards
Female Pelvis
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Where does the ureter enter the bladder?
posterolaterally
Male Pelvis
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mALE pELVIS
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Posterior Relations of the bladder in males:
- ductus deferens (runs through the
inguinal canal, below bladder and
attaches to seminal vesicles) - seminal vesicles (either side)
(connects to the prostate via) - ejaculatory ducts
Vesicouterine pouch is a
reflection of peritoneum
The uterus lies in an —— position
anteverted
(tips forward at the cervix)
How full does the bladder have to be to palpable and where does it protrude?
- 300ml
- anterior to the pubic symphysis
- strips the peritoneum of the
anterior bladder wall
What lies inferior to the bladder?
Levator ani (pelvic floor muscles)
Internal Bladder Anatomy
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Why does urine generally not reflux up the ureter?
- no valve
- inserts diagonally through detrusor
muscle wall - as bladder fills, pressure rises,
muscle will close the ureter opening
hence urine in distal ureter can not
reflux up
Trigone of bladder embryological origin:
mesoderm
What is the trigone?
- smooth triagnular region of bladder
- formed by two ureteric orifices and internal urethral orifice
- very sensitive to expansion, once
stretch signal to brain to need to
empty - signals become stronger as bladder
continues to fill
Bladder embryological origin:
endoderm (apart from trigone)
Where is the ureter in relation to uterine arteries?
- inferior
- bridge over water
Where is a potential site of ureteric injury in a hysterctomy?
Where the ureter runs under the uterine artery and vein
Female Pelvis
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Bladder mucosa is called
urithelium
bladder wall and epithelium
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Transitional cell epithelium is impermeable to
water and electrolytes due to a highly keratinised cellular membrane synthesised in the Golgi
Why is transitional cell epithelium impermeable?
importance in acting as an osmotic barrier between the contents of the urinary tract and surrounding organs/tissues
What is the most impermeable membrane in the mammalian body?
Transitional cell membrane (bladder)
Detrusor Muscle:
- longitudinal and circular smooth
muscle bundles - actin and myosin filaments aligned
loosely and anchored to dense
bodies - contraction shortens and thins the
whole cell - muscarinic M2&3 cholinergic
receptors - muscle cells connected by gap
junctions
Bladder Innervation: Sympathetic:
- L2 nerve root
- sympathetic ganglia
- hypogastric plexus
- Splanchnics: Lesser, Least, Lumbar
- relaxation of bladder (not empty)
Bladder Innervation: Parasympathetic:
- S2-4 nerve roots
- Pelvic Splanchnic nerves
- bladder contraction: emptying
Bladder Innervation: Somatic Supply:
- S2-4
- Pudendal Nerve: urethral sphincter
Bladder Innervation:
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Detrusor muscle cell alignment vs skeletal muscle
not sheets
muscle bundles
Bladder Receptors:
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Tablets use to inhibit bladder contraction act on M3 receptors so common side affect is
DRY MOUTH
inhibition of salivary glands
also have M3 receptors
Bladder Complaince:
bladder relaxes as it fills to allow storage
overdistension leads to renal retention
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Adaptations of Bladder Summary
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Guarding Reflex:
- neck of bladder
- bladder should empty to 0
- resting tone in external sphincter
- as the bladder fills, reflex increases
tone in external sphincter and
bladder muscle relaxes (no emptying)
What does the micturition reflex allow?
Bladder emptying
Micturition Reflex:
- once bladder reaches certain
volume and there is no cerebral
control of the bladder - the body of the bladder will
contract - neck of bladder, urethra and
sphincters will relax - bladder will empty
Where is the micturition reflex mediated?
Spinal cord
Micturition reflex only triggered in unconscious patients.
True or False?
True
Bladder Filling Phase
- guarding reflex: mediated by symp
and parasymp: PONTINE CENTER - orange = symp
- blue = para
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Voiding Phase:
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(box 2 not needed)
Types of Incontinence:
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Incontinence:
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Mechanisms of Drugs on the Bladder:
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Urge Incontinence Treatments: Diagram:
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- block M3 receptor: anticholinergics:
dry mouth, not storing urine better
because drinking more
- B3 agonist: reduce contraction
- botox detrusor muscle: reduce
contraction: overdose may need
catheterise
Stress Incontinence: Treatment:
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- mostly non-drug treatment
- surgery: more support to urethra
- nicotine agonist: fluoxetine: external
urethral sphincter: increase tone
Urinary Retention:
- BPH: Benign Prostatic hyperplasia,
enlarges, often bladder can
overcome - can lead to urine retention
- measured using a flow test
- most empty in 30secs
- can result in thickening of the
bladder wall - can result in diverticula
(outpouches) risk factor for stones - can transmit to high pressures in
ureter and kidney (hydronephrosis)
Urinary Retention:
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Urinary Retention: Treatment:
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- alpha blocker: relaxation of neck
- S alpha reductase inhibitor: works
on BPH, convert to testesterone to
dihydrotestosterone blocked so
reduce growth factors
