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Flashcards in Urinary Function (PKenny) Deck (12):

where does neurological control of the bladder originate?

Lumbosacral spine
- L1-L4, S1-S3
> hypogastric n. (L1-L4)
> pelvic n. (S1 - S3)
> pudendal n. (S1-S3)


What is the bladder and urethra made up of/controlled by?

> Bladder
- detrusor m. (smooth m)
> urethra
- internal urethral sphincter (smooth m)
- external urethral sphincter (skeletal m) controlled by pudendal n.


Where is the micturition centre located?

- receives input from cerebrum too


What NTs control the micturition reflex?

1. storage phase (sympathetic)
- bladder relaxed (B adrenergic Rs of hypogastric)
- urethra contracted (A adrenergic Rs of hypogastric and nicotinic cholinergic Rs of pudendal n)
+ inhibition of parasympathetic
2. voiding phase (parasympathetic)
- bladder contraction (Ach muscarinic cholinergic Rs of pelvic n.)
- relaxation of the urethra d/t lack of symp tone
+ inhibition of sympathetic fibres


What is UMN bladder?

Lesion anywhere from pons - L7
- UMN inhibition lost -> ^ tone
- turgid easily palpable bladder
- ^ urinary sphincter tone
- may be some overflow leakage


What is LMN bladder?

Lesion sacral SC or sacral nn. (seen with cauda equina syndrome)
- v tone
- flaccid, hard to palpate bladder
- v urinary sphincter tone
- passive leakage of urine


Problems associated with neurogenic bladder dysfunction?

- ncontinence
- urine scald
- urine stasis -> UTI -> pyelonephritis
- detrusor atony d/t over stretching of sm. m. tight junctions
- pain


How can voluntary micturition be distinguished from overflow?

Palpate bladder


Management of neurogenci bladder dysfunction

> physical management usually necesary
- manual expression
- urethral catheterisation (indwelling or permenetn)
- cystotomy tube (long term)
> pharmacological manipulation
- to assist manual


Give 5 drugs used to manipulate bladder function and their mechanisms of action

> diazepam
- centrally acting muscle relaxant
- v external urethral tone
- give 1 hr pre expressing bladder
> Bethanechol (?? off market now?)
- muscarinic cholinergic agonist (parasympathomimetic)
- facilitates detrusor muscle contractility
- do not give if ^ urethral tone will -> rupture
> Phenoxybenzamine and Prazosin
- a-adrenergic antagonist
- v internal urethral sphincter tone
- can use in conjunction with Bethanechol
> Phenylpropanolamine (PPA)
- mixed a+b adrenergic agonist
- ^ internal urethral sphincter tone
- tx of incontinence rather than urine retention


What does ^ protein in a CSF tap indicate?

Non specific sign


How can caudal sacral lesions be differentiated from nerve roots?

Cant really - v difficult
- could be L7-cauda equina or spinal n roots