Incontinence Flashcards
What anatomy is involved in continence?
bladder
urethra
pelvic floor muscles
nervous system
What type of system is the bladder?
Low pressure - High volume
Roughly what is the rate of bladder filling?
0.5-5ml/min = 30-300ml/hr
What is the capacity of the bladder?
600ml
At what volume does one desire to void?
250ml
How is continence maintained (very basically)?
urethral pressure is higher than bladder pressure
What occurs to allow micturition?
Relaxation of striated muscle around urethra and
pelvic floor muscle
and contraction of detrusor
What causes detrusor muscle to contract?
Bladder fills
signals parasympathetically to cause the
detrusor (smooth muscle) to contract
Where is the internal urethral sphincter (IUS) found?
junction of the urethra with the bladder
What makes up the IUS?
The detrusor, therefore its made of smooth muscle
What controls the IUS?
Autonomic NS (involuntary)
What urethral sphincter is the 1ry muscle for continence?
IUS
Where is the external urethral sphincter (EUS) located in males?
Inferior to the prostate
Where is the external urethral sphincter (EUS) located in females?
At the distal inferior end of the urethra
What type of muscle is the EUS?
Skeletal muscle
What is the problem with the EUS?
It is under voluntary control (as it is skeletal muscle) thus can relax when sneezing or coughing
Which area of the brain provides voluntary control of continence?
the frontal lobe (probably why pts with dementia are commonly incontinent)
Which part of the brain controls detrusor contraction and urethral relaxation?
the pontine micturition centre
Which part of the NS is responsible for micturition?
parasympathetic NS (for the involuntary side)
Which nerve is responsible for continence and what are its roots?
pudendal nerve
S2, 3, 4 (keep shit off the floor)
Where do the the parasympathetic nerves that control continence emerge form the spine?
The sacral plexus
Which subset of parasympathetic muscarinic receptor are responsible for bladder contraction?
M3
What nerves is bladder filling controlled by?
Sympathetic NS
Where do the sympathetic nerves relating to the bladder emerge and what do they do?
T11 - L2
Bladder neck contraction and
proximal urethral contraction