structure and function of the lower urinary tract part 1 W2 Flashcards

1
Q

what structures does the lower urinary tract include

A

bladder, urethra

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2
Q

what does the urethra have protection from

A

fascia, pubic ramus (anterior), iliac wings (posterior)

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3
Q

where does the peritoneum lie in relationship to the bladder

A

superiorly

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4
Q

what forms the borders of the trigone

A

ureteral openings/orifices
internal urethral meatus

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5
Q

layers of the bladder?

A

transitional epithelium / urothelium
lamina propria

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6
Q

difference in the detrusor muscle between sexes? why?

A

male detrusor thicker as works against resistance from prostate gland

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7
Q

bladder apical membrane features

A

important role in cellular signalling
signals sent via tight junctions

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8
Q

papillary bladder tumour symptoms?

A

painless visible haematuria
bladder discomfort
urgency and frequency to pass urine

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9
Q

layers of the bladder wall?

A

urothelium
lamina propria
detrusor muscle and stroma
adventitia/serosa

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10
Q

urothelium features

A

multi-layered epithelium
apical (umbrella cells)
functions - barrier, afferent signalling

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11
Q

lamina propria features

A

functional centre coordinating urothelium and detrusor
contains blood vessels, nerve fibres and myofibroblasts

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12
Q

detrusor muscle and stroma features

A

smooth muscle arranged in bundles
functional syncytium
each detrusor cell 600x5 microns
stroma - collagen and elastin
innervation of muscle = postganglionic parasympathetic system

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13
Q

normal bladder functions?

A

compliant reservoir for urine storage
barrier function
volitional voiding (muscular function)

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14
Q

barrier function of bladder?

A

GAG layer, tight junctions
passive passage of urea, Na, K
resists water passage but not truly waterproof
damage to urothelium - role in disease

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15
Q

how does the bladder store urine at a low pressure

A

highly compliant (dependant on visco-elastic properties of the bladder and relaxation of the detrusor)

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16
Q

neurology of bladder

A

bladder filling sensors detect increase in wall tension
afferent neurons to dorsal horn of sacral spinal cord
sensory/real time data on bladder state relayed to brainstem and higher centres

17
Q

volitional (voluntary) micturition/voiding?

A

spino-bulbar reflex
modulation by pontine micturition centre (barringtons nucleus)
onufs nucleus in intermediolateral S2,3,4

18
Q

when does the bladder feel full/uncomfortable?

A

fullness at 250ml
uncomfortable at 500ml (can lead to involuntary detrusor contractions)

19
Q

what occurs during voiding

A

detrusor contraction
urethral relaxation
relaxation of external urethral sphincter
urine enters posterior urethra

20
Q

what areas of the brain are involved in micturition? (urinating)

A

prefrontal, hypothalamic, thalamic, cerebellar areas and pons (most importantly)

21
Q

neurotransmitters involved in bladder function?

A

acetylcholine - excitatory
role for nitric oxide in relaxation of bladder neck/EUS
GABA and glycine - inhibitory

22
Q

facilitation and inhibition

A

facilitation - contraction of detrusor and relaxation of sphincter when bladder is less than full (eg anxious states)
inhibition - postponement of voiding

23
Q

what happens when control of voiding from higher centres is lost?

A

control by spinobulbar reflexes
typically reflex voiding (not socially convenient)
can be caused by spinal cord injuries

24
Q

spinal cord lesions leading to different clinical features for voiding?

A

suprapontine lesion
spinal (infrapontine-suprasacral) lesion
sacral/infrasacral lesion

25
Q

suprapontine lesion features?

A

predominantly storage symptoms
insignificant PVR urine volume
detrusor overactivity

26
Q

spinal (infrapontine-suprasacral) lesion features?

A

both storage and voiding symptoms
PVR urine volume normally raised
detrusor overactivity, detrusor-sphincter dyssynergia

27
Q

sacral/infrasacral lesion features

A

predominantly voiding symptoms
PVR urine volume raised
hypocontractile or acontractile detrusor

28
Q

PVR?

A

post void residual volume
seen on ultrasound