Physiology of Micturition Flashcards
(139 cards)
1
Q
Label this diagram [PM1]
A
A - Median umbilical ligament B - Ureter C - Peritoneum D - Detrusor muscle E - Ureteral openings F - Trigone G - Neck of urinary bladder H - Internal urethral sphincter I - External urethral sphincter (in urogenital diaphragm) J - Muscosa Ji - Transitional epithelium Jii - Lamina propria Jiii - Adventitia K - Detrusor muscle L - Adventitia
1 - Body
2 - Trigone
3 - Neck
2
Q
What is the purpose of the body of the bladder?
A
Temporary store of urine
3
Q
What are at the angles of the trigone area?
A
Ureteric orifaces and internal urethral orifice
4
Q
What does the neck of the bladder do?
A
Connects the bladder to the urethra
5
Q
What is the detrusor urinae muscle made from?
A
A meshwork of muscle fibres in roughly 3 layers
6
Q
What are the layers of the detrusor urinae muscle?
A
Inner longitudinal
Middle circular
Outer longitudinal
7
Q
What does the arrangement of muscle fibres of the detrusor muscle give?
A
The bladder strength, irrespective of the direction it’s being stretched in
8
Q
What is the detrusor urinae muscle supplied by?
A
The autonomic nervous system
9
Q
Is the detrusor urinae muscle under voluntary control?
A
No
10
Q
Is the spinal nerve supply of the detrusor urinae muscle unilateral or bilateral?
A
Bilateral
11
Q
Label this diagram [PM2]
A
A and B (lol oops) - Transitional Epithelium
C - Mucosa
D - Submucosa
1 - Inner layer of longitudinal muscle
2 - Middle layer of circular muscle
3 - Outer layer of longitudinal muscle
12
Q
What is the internal urethral sphincter a continuation of?
A
The detrusor muscle
13
Q
What is the internal urethral sphincter made of?
A
Smooth muscle
14
Q
What kind of sphincter is the internal urethral sphincter?
A
Physiological
15
Q
What is meant by the internal urethral sphincter being a physiological sphincter?
A
There is no muscle thickening, the action is due to structure
16
Q
Where is the internal urethral sphincter found?
A
At the bladder neck
17
Q
What is the importance of the internal urethral sphincter?
A
It is the primary muscle of continence
18
Q
What kind of sphincter is the external urethral sphincter?
A
Anatomical sphincter
19
Q
What facilitates the action of the external urethral sphincter?
A
Localised circular muscle thickening
20
Q
What is the external urethral sphincter derived from?
A
The pelvic floor muscles
21
Q
What kind of muscle is the external urethral sphincter?
A
Skeletal muscle
22
Q
What control is the external urethral sphincter under?
A
Somatic, voluntary control
23
Q
How does the external urethral sphincter work?
A
Contracts to constrict urethra and ‘hold in urine’
24
Q
What are the kinds of innervation of the detrusor muscle?
A
Parasympathetic
Sympathetic
25
What is the parasympathetic innervation of the detrusor muscle?
Pelvic nerve (S2-S4)
26
What is the result of pelvic nerve stimulation to the detrusor muscle?
ACh simulates M3 receptors
27
What is the result of stimulation of M3 receptors at the detrusor muscle?
Contraction
28
What is the sympathetic innervation to the detrusor muscle?
Hypogastric nerve (T10-L2)
29
What is the result of hypogastric nerve stimulation of the detrusor muscle?
NA stimulates ß3-receptors
30
What is the result of stimulation of ß3 receptors at the detrusor muscle?
Relaxation
31
What is the type of innervation of the internal urethral sphincter?
Sympathetic, via hypogastric nerve (T10-L2)
32
What is the result of hypogastric nerve stimulation to the internal urethral sphincter?
NA stimulates alpha-1 receptors
33
What is the result of alpha-1 receptor stimulation of the internal urethral sphincter?
Contraction
34
What kind of innervation does the external urethral sphincter receive?
Somatic
35
What is the somatic innervation of the external urethral sphincter?
Pudendal nerve (S2-S4)
36
Where does the spinal motor outflow come from with the pudendal nerve supply of the external urethral sphincter?
Onof's nucleus of the ventral horn of the cord
37
What is the result of pudendal nerve stimulation to the external urethral sphincter?
ACh stimulates the nicotinic receptor
38
What is the result of the stimulation of the nicotinic receptor ion the external urethral sphincter?
Contraction
39
Label this diagram illustrating the innervation of the bladder [PM3]
```
A - ACh
B - Bladder
C - M3 receptor (+)
D - ß3 receptor (-)
E - Detrusor muscle
F - Urethra
G - alpha-1 receptor (+)
H - External urethral sphincter
J - Nicotinic receptor (+)
K - ACh
L - NA
M - NA
```
1 - Pelvic nerve (parasympathetic)
2 - Hypogastric nerve (sympathetic)
3 - Pudendal nerve (somatic)
40
What is the threshold for feelings suggestive of a full bladder?
~400ml
41
What happens when the bladder is full?
An urge to urinate arises
42
What is the nervous stimulation for the urge to urinate?
Brain micturition centres → Spinal micturition centres → Parasympathetic neurones
43
How to parasympathetic neurones cause the urge to urinate?
The increase in parasympathetic stimulation to the bladder via the pelvic nerve causes the detrusor muscle to contract and increase intravesicular pressure
44
What is the conscious aspect of micturition?
The external urethral sphincter
45
What controls the external urethral sphincter?
The cerebral cortex
46
How does the cerebral cortex control the external urethral sphincter?
The cerebral cortex makes a conscious, executive decision to urinate, reducing somatic stimulation to the external urethral sphincter
47
What does the contraction of the detrusor coupled with the relaxation of the external urethral sphincter result in?
Emptying through the urethra
48
What works together to pass urine into the urinary bladder?
The ureters, urinary bladder, and internal and external urethral sphincter
49
How long can urine be stored in the urinary bladder?
Many hours
50
When may urine need to be stored for many hours?
At night
51
What feature do the walls of the bladder have?
Many folds
52
What happens to the walls of the bladder when filling with urine?
The folds allow distension
53
What is the result of the distention of the bladder wall on filling with urine?
As the bladder fills, intravesicular pressure hardly changes
54
What happens at around 400ml of filling?
Afferent nerves from the bladder wall start to signal the need to void the bladder
55
What kind of receptors are those of the afferent nerves from the bladder wall?
Possible stretch receptors
56
What signals are sent to show the need to void the bladder?
Pain/temperature sensation
57
Where does the signal from the afferent nerves from the bladder wall go?
Brain continence centres
58
What pathway does the nervous stimulation signalling the need to void the bladder take from the brain continence centres?
Brain continence centre → Spinal continence centre → Sympathetic neurones
59
How do sympathetic neurones cause continence?
The increase in sympathetic stimulation to the bladder via the hypogastric nerve causes the detrusor muscle to relax and the internal urethral sphincter to contract
60
What is the cerebral cortex's role in storage of urine in the bladder?
The cerebral cortex makes a conscious, executive decision not to urinate, increasing somatic stimulation to the external urethral sphincter. This causes it to contract, constricting the urethra
61
What does the relaxation of the detrusor and the contraction of the internal and external urethral sphincters lead to?
Reduced intravesicular pressure and constriction of urethra, preventing micturition
62
What are the types of incontinence?
Stress urinary incontinence
Urge urinary incontinence
Mixed urinary continence
Overflow incontinence
63
What is stress urinary incontinence?
Involuntary leakage on effort or exertion, or on sneezing or coughing
64
What is urge urinary incontinence?
Involuntary leakage, accompanied by or immediately proceeded by urgency
65
What is mixed urinary incontinence?
Involuntary leakage, associated with urgency and exertion, effort, sneezing or coughing
66
What is overflow incontinence?
Retention of urine causing the bladder to swell. Can be low pressure and pain free
67
What is the most common type of incontinence?
Stress urinary incontinence
68
What % of incontinence is stress urinary incontinence?
47%
69
What % of incontinence is urge urinary incontinence?
21%
70
What % of incontinence is mixed urinary incontinence?
28%
71
What % of incontinence is overflow incontinence?
4%
72
What happens to the prevalence of urinary incontinence with age?
It steadily increases
73
What do the risk factors for urinary incontinence include?
Anything that can weaken the pelvic floor muscles
74
Give an example of something that can weaken the pelvic floor muscles
Childbirth
75
Why can the weakening of the pelvic floor muscles lead to incontinence?
The support of the urethra by the muscles and ligaments of the pelvic floor are important for efficiency of the sphincter mechanisms of the urethra that enable continence
76
What are the categories of risk factors for urinary incontinence?
Obstetrics and gynaecology
Predisposing
Promoting
77
What are the obgyn risk factors for urinary incontinence?
Pregnancy and childbirth
Pelvic surgery/DXT (no elliot i dont know what this acronym means)
Pelvic prolapse
78
What are the predisposing risk factors for urinary incontinence?
Race
Family predisposition
Anatomical abnormalities
Neurological abnormalities
79
What are the promoting risk factors for urinary incontinence?
```
Co-morbidities
Obesity
Age
Increase intra-abdo pressure
Cognitive impairment
UTI
Drugs
Menopause
```
80
What can be used to assess the frequency of micturition in a patient history?
Asking the patient to record the amount of fluid they pass for two or three days
81
How can incontinence be judged?
The number of pads that the person has to use per day to cope with urine leakage
82
What are the types of urinary incontinence leaking?
Continuous or intermittent
83
How can the type of UI be categorised?
Wether the leakage is continuous or intermittent
| What precipitating factors there are
84
When will urgency and frequency of micturition often be made worse?
If there is an intravesicular inflammatory condition
85
Give three examples of intravesicular inflammatory conditions
Urinary tract infections
Stone in the bladder
Tumour
86
Why can previous surgery of the pelvic floor be important in urinary incontinence?
May lead to denervation of parts of bladder
87
Why may childbirth be an important factor in the development of stress urinary incontinence in women?
Due to sphincter damage
88
How should a examination be conducted when a patient presents with urinary incontinence?
Height/weight
Abdominal exam to exclude palpable bladder
Digital rectal examination
In females, external genitalia stress tests, an vaginal exam
89
What should be checked for when performing a digital rectal examination?
Prostate in male
| Limited neurological examination
90
What are the mandatory investigations when someone presents with urinary incontinence?
Urine dipstick
91
What is being looked for with a urine dipstick for urinary incontinence?
UTI
Haematuria
Proteinuria
Glucosuria
92
What are the basic non-invasive urodynamic investigations for urinary incontinence?
Frequency-volume chart
Bladder diary
Post micturition residual volume
93
How long is a bladder diary conducted for when a patient has urinary incontinence?
~3 days
94
When is a post micturition residual volume test conducted?
In patients with voiding dysfunction
95
What are the optional investigations in a patient with urinary incontinence?
Invasive urodynamics
Pad tests
Cystoscopy
96
What do invasive urodynamics consist of?
Pressure-flow studies, with or without video
97
What does the management of urinary incontinence depend on?
Which symptoms the patient has
The degree of bother they cause
Previous or current treatments
The effects of treatments on any other symptoms they may have
98
What is it important to do with the management of urinary incontinence?
Should be individualised, with a systematic approach
99
What are the conservative management strategies for urinary incontinence?
```
General lifestyle interventions;
Modify fluid intake
Weight loss
Stop smoking
Decrease caffeine intake
Avoid constipation
Time voiding- fixed schedule
```
100
How should contained incontinence management strategies be considered for?
Patients unsuitable for surgery who have failed conservation or medical management?
101
What are the contained incontinence methods of urinary incontinence management?
Indwelling catheter
Sheath device
Incontinence pads
102
Where can an indwelling catheter be inserted?
Urethral or suprapubic
103
What is a sheath device?
Analogous to an adhesive condom attached to a catheter tubing and bag
104
What is involved in the specific management of stress urinary incontinence?
Pelvic floor muscles training
105
What does pelvic floor muscle training consist of?
8 contractions, 3x a day
| At least 3 months duration
106
What are the muscles used in pelvic floor training responsible for in micturition?
Void bladder, stop stream
107
What are the methods of specific management of urge urinary incontinence?
Bladder training
Schedule of voiding
At least 6 weeks of training needed
108
What schedule of voiding is used in the specific management of urge urinary incontinence?
Void every hour during the day
Must not void in between - wait or leak
Intervals increased by 15-30 minutes a week, until interval of 2-3 hours
109
What drugs are used in the management of patients with urinary incontinence?
Duloxetine
Anticholinergics
Botulinum toxin
110
What is duloxetine?
A combined noradrenaline and serotonin uptake inhibitor
111
What does duloxetine do?
Increases the activity of the external urethral sphincter during the filling phase
112
What are the NICE recommendations regarding duloxetine?
Not recommended by NICE as a first line, or routine second line treatment, but may be offered as an alternative to surgery
113
What do anticholinergics act on?
Muscarinic receptors, including those M3 receptors that cause the detrusor to contract
114
What is the problem with anticholinergics in the treatment of urinary incontinence?
Many side effects due to effects on M receptors at other sites
115
Give an example of an anticholinergic
Oxybutynin
116
What is botulinum toxin?
A potent biological neurotoxin that inhibits ACh release
117
How does botulinum toxin treat urinary incontinence?
Prevents detrusor muscle contraction
118
Why does the botulinum toxin prevent detrusor muscle contraction?
As the pelvic nerve cannot release ACh to act on the M3 receptors
119
What are the types of surgical management techniques for urinary incontinence in females?
Permanent intention
| Temporary intention
120
What are the permanent intention surgical techniques used to treat urinary incontinence in females?
Low-tension vaginal tapes
Open retropubic suspension procedures
Classic fascial sling procedures
121
What is the most common surgical intervention for urinary incontinence in females?
Low-tension vaginal tapes
122
Why are low-tension vaginal tapes so common?
Minimally invasive
| Success rate of >90%
123
How do low-tension vaginal tapes work?
By supporting the mid urethra with polypropylene mesh
124
How does the open retropubic suspension procedure surgical intervention work?
It corrects the anatomical position of the proximal urethra and improves urethral support
125
What does the classic fascial sling procedure do?
Supports the urethra and increases bladder outflow resistance
126
What does the classic fascial sling procedure involve?
Autologous transplantation of the fascia lata or rectus fascia
127
What are the temporary intention surgery procedures to correct urinary incontinence in females?
Intramural bulking agents
128
What do intramural bulking agents do?
Improve the ability of the urethra to resist abdominal pressure by improving urethral coaptation
129
How is improved urethral coaptation achieved with intramural bulking agents?
By injections of autologous fat, collagen, or hyaluron-dextan polymers
130
What are the surgical interventions to treat urinary incontinence in males?
Artificial urinary sphincter
| Male sling procedure
131
Where is an artificial urinary sphincter the gold standard treatment?
In urethral sphincter deficiency
132
What is an artificial urinary sphincter?
A mechanical (hydraulic) device
133
How does an artificial urinary sphincter work?
It stimulates the action of a normal sphincter to circumferentially close the urethra
134
What are the potential problems with artificial urethral sphincters?
Infection
Erosion
Device failure
135
What does the male sling procedure do?
Corrects stress urinary incontinence
136
What is usually the cause of stress urinary incontinence in males?
Iatrogenic
137
What are the iatrogenic of stress urinary incontinence in males?
Radical prostatectomy
Colorectal surgery
Radical pelvic radiotherapy
138
What does the male sling procedure use?
Bone-anchored tape
139
What is the problem with the male sling procedure?
It is an experimental/emerging treatment, and the long-term results are unknown
