Micturation (Cooke) Flashcards
1
Q
Detrusor muscle
A
- makes up the bladder
- has tight junctions
2
Q
Urethra
A
- ‘internal sphincter’
- has many components
- external sphincter
- striated muscle
- voluntary control of urination
3
Q
Bladder position
A
- normal position is important
- abdominal pressure presses on neck of bladder as well
4
Q
Uretovesicular junction
A
- ureters need to be located behind the sphincters for an animal to be continant
5
Q
Receptors in the wall of the bladder
A
- Beta receptors
- stimulation of these receptors cause relaxation of detrusor muscle
6
Q
Receptors in the internal urethral sphincter
A
- alpha receptors
- stimulation causes contraction/inc tone in smooth muscle of urethral sphincter
7
Q
Hypogastric nerve
A
- Comes from Lumbar cord segments 1-4 or 5 I think
- Sympathetic nervous system
- Excites B and alpha receptors on bladder and internal urethral sphincter
- sensory functions
- inflammation
- stretch
8
Q
Pelvic nerve
A
- part of the parasympathetic nervous system
- primary nuerotransmitter is acetylcholine
- Comes from Sacral Cord segements 1-3
- synapses on cholinergic receptors in detrusor muscle
- stimulation creates contraction of detrusor muscle
- sensory fibers
- sense normal stretch of filling bladder
9
Q
Pudendal nerve
A
- Comes from sacral segments
- Primarily somatic and motor fibers to external sphincter
- some sensory fibers
- urethra and neck of bladder
- responsible for voluntary control of bladder
10
Q
Phases of normal micturition
A
- Storage phase
- sympathetic dominance => hypogastric N.
- plus pudendal nerve => voluntary control
- Voiding phase (sensory)
- distention => pelvic nerve
- pain and overdistension => hypogastric nerve - cerebral cortex
- pons => to spinal cord => to pelvic n.
- Voiding phase (motor)
- coordinated response of
- bladder contraction
- urethral relaxation
- coordinated response of
11
Q
Following the schematic (normal micturition)
A
- Pelvic n. can sense distention
- Hypogastric n. can sense pain or over distension - carried up to brain
- Brain sends stimulus to hypogastric, pelvic, pudendal nerve
- inhibition of the hypogastric nerve - inhibition of tone in internal sphincter (alpha receptors)
- inhibition of pudendal n. for relaxation of external sphincter
- stimulation of pelvic nerve, release of achetylcholine and contraction of bladder
12
Q
disorders of micturition
Storage disorders
A
- components of normal storage
- ureteral position
- detrusor relaxation
- adequate urethral closure/tone
13
Q
Characteristics of storage disorders
A
- Voluntary urination is normal
- no stranguria, pollakiuria
- involuntary leakage
- normal residual volume
- post urination, blatter should be small
14
Q
disorders of micturition
voiding disorders
A
- components of normal voiding
- detrusor contraction
- urethral relaxation
- physical obstruction
15
Q
Characteristics of voiding disorders
A
- voluntary urination abdormal
- stranguria
- pollakiuria
- diminished urine stream
- usually postures
- Increased residual volume
16
Q
Clinical approach
A
- consider age
- young: congenital or housebreaking issues
- adult: acquired
17
Q
Questions to ask on a history
A
- When did it start?
- When does it occur?
- Urine stream?
- Awareness?
- Frequency?
- Volume?
- Straining, blood?
- Other problems?
18
Q
Physical exam elements
A
- Bladder size / tone
- before / after urination
- Perineal / preputial wetness / staining
- Rectal exam
- +/- vaginal exam
- especially if patient will be sedated for other purposes
- Neurological exam
- check anal tone
- check perineal reflex - retraction if you touch around anus
