Physiology of Micturition Flashcards

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

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2
Q

What is the purpose of the body of the bladder?

A

Temporary store of urine

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3
Q

What are at the angles of the trigone area?

A

Ureteric orifaces and internal urethral orifice

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4
Q

What does the neck of the bladder do?

A

Connects the bladder to the urethra

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5
Q

What is the detrusor urinae muscle made from?

A

A meshwork of muscle fibres in roughly 3 layers

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6
Q

What are the layers of the detrusor urinae muscle?

A

Inner longitudinal
Middle circular
Outer longitudinal

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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

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8
Q

What is the detrusor urinae muscle supplied by?

A

The autonomic nervous system

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9
Q

Is the detrusor urinae muscle under voluntary control?

A

No

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10
Q

Is the spinal nerve supply of the detrusor urinae muscle unilateral or bilateral?

A

Bilateral

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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

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12
Q

What is the internal urethral sphincter a continuation of?

A

The detrusor muscle

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13
Q

What is the internal urethral sphincter made of?

A

Smooth muscle

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14
Q

What kind of sphincter is the internal urethral sphincter?

A

Physiological

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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

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16
Q

Where is the internal urethral sphincter found?

A

At the bladder neck

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17
Q

What is the importance of the internal urethral sphincter?

A

It is the primary muscle of continence

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18
Q

What kind of sphincter is the external urethral sphincter?

A

Anatomical sphincter

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19
Q

What facilitates the action of the external urethral sphincter?

A

Localised circular muscle thickening

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20
Q

What is the external urethral sphincter derived from?

A

The pelvic floor muscles

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21
Q

What kind of muscle is the external urethral sphincter?

A

Skeletal muscle

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22
Q

What control is the external urethral sphincter under?

A

Somatic, voluntary control

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23
Q

How does the external urethral sphincter work?

A

Contracts to constrict urethra and ‘hold in urine’

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24
Q

What are the kinds of innervation of the detrusor muscle?

A

Parasympathetic

Sympathetic

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25
Q

What is the parasympathetic innervation of the detrusor muscle?

A

Pelvic nerve (S2-S4)

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26
Q

What is the result of pelvic nerve stimulation to the detrusor muscle?

A

ACh simulates M3 receptors

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27
Q

What is the result of stimulation of M3 receptors at the detrusor muscle?

A

Contraction

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28
Q

What is the sympathetic innervation to the detrusor muscle?

A

Hypogastric nerve (T10-L2)

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29
Q

What is the result of hypogastric nerve stimulation of the detrusor muscle?

A

NA stimulates ß3-receptors

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30
Q

What is the result of stimulation of ß3 receptors at the detrusor muscle?

A

Relaxation

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31
Q

What is the type of innervation of the internal urethral sphincter?

A

Sympathetic, via hypogastric nerve (T10-L2)

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32
Q

What is the result of hypogastric nerve stimulation to the internal urethral sphincter?

A

NA stimulates alpha-1 receptors

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33
Q

What is the result of alpha-1 receptor stimulation of the internal urethral sphincter?

A

Contraction

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34
Q

What kind of innervation does the external urethral sphincter receive?

A

Somatic

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35
Q

What is the somatic innervation of the external urethral sphincter?

A

Pudendal nerve (S2-S4)

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36
Q

Where does the spinal motor outflow come from with the pudendal nerve supply of the external urethral sphincter?

A

Onof’s nucleus of the ventral horn of the cord

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37
Q

What is the result of pudendal nerve stimulation to the external urethral sphincter?

A

ACh stimulates the nicotinic receptor

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38
Q

What is the result of the stimulation of the nicotinic receptor ion the external urethral sphincter?

A

Contraction

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39
Q

Label this diagram illustrating the innervation of the bladder [PM3]

A
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)

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40
Q

What is the threshold for feelings suggestive of a full bladder?

A

~400ml

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41
Q

What happens when the bladder is full?

A

An urge to urinate arises

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42
Q

What is the nervous stimulation for the urge to urinate?

A

Brain micturition centres → Spinal micturition centres → Parasympathetic neurones

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43
Q

How to parasympathetic neurones cause the urge to urinate?

A

The increase in parasympathetic stimulation to the bladder via the pelvic nerve causes the detrusor muscle to contract and increase intravesicular pressure

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44
Q

What is the conscious aspect of micturition?

A

The external urethral sphincter

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45
Q

What controls the external urethral sphincter?

A

The cerebral cortex

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46
Q

How does the cerebral cortex control the external urethral sphincter?

A

The cerebral cortex makes a conscious, executive decision to urinate, reducing somatic stimulation to the external urethral sphincter

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47
Q

What does the contraction of the detrusor coupled with the relaxation of the external urethral sphincter result in?

A

Emptying through the urethra

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48
Q

What works together to pass urine into the urinary bladder?

A

The ureters, urinary bladder, and internal and external urethral sphincter

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49
Q

How long can urine be stored in the urinary bladder?

A

Many hours

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50
Q

When may urine need to be stored for many hours?

A

At night

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51
Q

What feature do the walls of the bladder have?

A

Many folds

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52
Q

What happens to the walls of the bladder when filling with urine?

A

The folds allow distension

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53
Q

What is the result of the distention of the bladder wall on filling with urine?

A

As the bladder fills, intravesicular pressure hardly changes

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54
Q

What happens at around 400ml of filling?

A

Afferent nerves from the bladder wall start to signal the need to void the bladder

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55
Q

What kind of receptors are those of the afferent nerves from the bladder wall?

A

Possible stretch receptors

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56
Q

What signals are sent to show the need to void the bladder?

A

Pain/temperature sensation

57
Q

Where does the signal from the afferent nerves from the bladder wall go?

A

Brain continence centres

58
Q

What pathway does the nervous stimulation signalling the need to void the bladder take from the brain continence centres?

A

Brain continence centre → Spinal continence centre → Sympathetic neurones

59
Q

How do sympathetic neurones cause continence?

A

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
Q

What is the cerebral cortex’s role in storage of urine in the bladder?

A

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
Q

What does the relaxation of the detrusor and the contraction of the internal and external urethral sphincters lead to?

A

Reduced intravesicular pressure and constriction of urethra, preventing micturition

62
Q

What are the types of incontinence?

A

Stress urinary incontinence
Urge urinary incontinence
Mixed urinary continence
Overflow incontinence

63
Q

What is stress urinary incontinence?

A

Involuntary leakage on effort or exertion, or on sneezing or coughing

64
Q

What is urge urinary incontinence?

A

Involuntary leakage, accompanied by or immediately proceeded by urgency

65
Q

What is mixed urinary incontinence?

A

Involuntary leakage, associated with urgency and exertion, effort, sneezing or coughing

66
Q

What is overflow incontinence?

A

Retention of urine causing the bladder to swell. Can be low pressure and pain free

67
Q

What is the most common type of incontinence?

A

Stress urinary incontinence

68
Q

What % of incontinence is stress urinary incontinence?

A

47%

69
Q

What % of incontinence is urge urinary incontinence?

A

21%

70
Q

What % of incontinence is mixed urinary incontinence?

A

28%

71
Q

What % of incontinence is overflow incontinence?

A

4%

72
Q

What happens to the prevalence of urinary incontinence with age?

A

It steadily increases

73
Q

What do the risk factors for urinary incontinence include?

A

Anything that can weaken the pelvic floor muscles

74
Q

Give an example of something that can weaken the pelvic floor muscles

A

Childbirth

75
Q

Why can the weakening of the pelvic floor muscles lead to incontinence?

A

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
Q

What are the categories of risk factors for urinary incontinence?

A

Obstetrics and gynaecology
Predisposing
Promoting

77
Q

What are the obgyn risk factors for urinary incontinence?

A

Pregnancy and childbirth
Pelvic surgery/DXT (no elliot i dont know what this acronym means)
Pelvic prolapse

78
Q

What are the predisposing risk factors for urinary incontinence?

A

Race
Family predisposition
Anatomical abnormalities
Neurological abnormalities

79
Q

What are the promoting risk factors for urinary incontinence?

A
Co-morbidities 
Obesity 
Age
Increase intra-abdo pressure 
Cognitive impairment
UTI
Drugs
Menopause
80
Q

What can be used to assess the frequency of micturition in a patient history?

A

Asking the patient to record the amount of fluid they pass for two or three days

81
Q

How can incontinence be judged?

A

The number of pads that the person has to use per day to cope with urine leakage

82
Q

What are the types of urinary incontinence leaking?

A

Continuous or intermittent

83
Q

How can the type of UI be categorised?

A

Wether the leakage is continuous or intermittent

What precipitating factors there are

84
Q

When will urgency and frequency of micturition often be made worse?

A

If there is an intravesicular inflammatory condition

85
Q

Give three examples of intravesicular inflammatory conditions

A

Urinary tract infections
Stone in the bladder
Tumour

86
Q

Why can previous surgery of the pelvic floor be important in urinary incontinence?

A

May lead to denervation of parts of bladder

87
Q

Why may childbirth be an important factor in the development of stress urinary incontinence in women?

A

Due to sphincter damage

88
Q

How should a examination be conducted when a patient presents with urinary incontinence?

A

Height/weight
Abdominal exam to exclude palpable bladder
Digital rectal examination
In females, external genitalia stress tests, an vaginal exam

89
Q

What should be checked for when performing a digital rectal examination?

A

Prostate in male

Limited neurological examination

90
Q

What are the mandatory investigations when someone presents with urinary incontinence?

A

Urine dipstick

91
Q

What is being looked for with a urine dipstick for urinary incontinence?

A

UTI
Haematuria
Proteinuria
Glucosuria

92
Q

What are the basic non-invasive urodynamic investigations for urinary incontinence?

A

Frequency-volume chart
Bladder diary
Post micturition residual volume

93
Q

How long is a bladder diary conducted for when a patient has urinary incontinence?

A

~3 days

94
Q

When is a post micturition residual volume test conducted?

A

In patients with voiding dysfunction

95
Q

What are the optional investigations in a patient with urinary incontinence?

A

Invasive urodynamics
Pad tests
Cystoscopy

96
Q

What do invasive urodynamics consist of?

A

Pressure-flow studies, with or without video

97
Q

What does the management of urinary incontinence depend on?

A

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
Q

What is it important to do with the management of urinary incontinence?

A

Should be individualised, with a systematic approach

99
Q

What are the conservative management strategies for urinary incontinence?

A
General lifestyle interventions; 
Modify fluid intake
Weight loss
Stop smoking
Decrease caffeine intake 
Avoid constipation 
Time voiding- fixed schedule
100
Q

How should contained incontinence management strategies be considered for?

A

Patients unsuitable for surgery who have failed conservation or medical management?

101
Q

What are the contained incontinence methods of urinary incontinence management?

A

Indwelling catheter
Sheath device
Incontinence pads

102
Q

Where can an indwelling catheter be inserted?

A

Urethral or suprapubic

103
Q

What is a sheath device?

A

Analogous to an adhesive condom attached to a catheter tubing and bag

104
Q

What is involved in the specific management of stress urinary incontinence?

A

Pelvic floor muscles training

105
Q

What does pelvic floor muscle training consist of?

A

8 contractions, 3x a day

At least 3 months duration

106
Q

What are the muscles used in pelvic floor training responsible for in micturition?

A

Void bladder, stop stream

107
Q

What are the methods of specific management of urge urinary incontinence?

A

Bladder training
Schedule of voiding
At least 6 weeks of training needed

108
Q

What schedule of voiding is used in the specific management of urge urinary incontinence?

A

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
Q

What drugs are used in the management of patients with urinary incontinence?

A

Duloxetine
Anticholinergics
Botulinum toxin

110
Q

What is duloxetine?

A

A combined noradrenaline and serotonin uptake inhibitor

111
Q

What does duloxetine do?

A

Increases the activity of the external urethral sphincter during the filling phase

112
Q

What are the NICE recommendations regarding duloxetine?

A

Not recommended by NICE as a first line, or routine second line treatment, but may be offered as an alternative to surgery

113
Q

What do anticholinergics act on?

A

Muscarinic receptors, including those M3 receptors that cause the detrusor to contract

114
Q

What is the problem with anticholinergics in the treatment of urinary incontinence?

A

Many side effects due to effects on M receptors at other sites

115
Q

Give an example of an anticholinergic

A

Oxybutynin

116
Q

What is botulinum toxin?

A

A potent biological neurotoxin that inhibits ACh release

117
Q

How does botulinum toxin treat urinary incontinence?

A

Prevents detrusor muscle contraction

118
Q

Why does the botulinum toxin prevent detrusor muscle contraction?

A

As the pelvic nerve cannot release ACh to act on the M3 receptors

119
Q

What are the types of surgical management techniques for urinary incontinence in females?

A

Permanent intention

Temporary intention

120
Q

What are the permanent intention surgical techniques used to treat urinary incontinence in females?

A

Low-tension vaginal tapes
Open retropubic suspension procedures
Classic fascial sling procedures

121
Q

What is the most common surgical intervention for urinary incontinence in females?

A

Low-tension vaginal tapes

122
Q

Why are low-tension vaginal tapes so common?

A

Minimally invasive

Success rate of >90%

123
Q

How do low-tension vaginal tapes work?

A

By supporting the mid urethra with polypropylene mesh

124
Q

How does the open retropubic suspension procedure surgical intervention work?

A

It corrects the anatomical position of the proximal urethra and improves urethral support

125
Q

What does the classic fascial sling procedure do?

A

Supports the urethra and increases bladder outflow resistance

126
Q

What does the classic fascial sling procedure involve?

A

Autologous transplantation of the fascia lata or rectus fascia

127
Q

What are the temporary intention surgery procedures to correct urinary incontinence in females?

A

Intramural bulking agents

128
Q

What do intramural bulking agents do?

A

Improve the ability of the urethra to resist abdominal pressure by improving urethral coaptation

129
Q

How is improved urethral coaptation achieved with intramural bulking agents?

A

By injections of autologous fat, collagen, or hyaluron-dextan polymers

130
Q

What are the surgical interventions to treat urinary incontinence in males?

A

Artificial urinary sphincter

Male sling procedure

131
Q

Where is an artificial urinary sphincter the gold standard treatment?

A

In urethral sphincter deficiency

132
Q

What is an artificial urinary sphincter?

A

A mechanical (hydraulic) device

133
Q

How does an artificial urinary sphincter work?

A

It stimulates the action of a normal sphincter to circumferentially close the urethra

134
Q

What are the potential problems with artificial urethral sphincters?

A

Infection
Erosion
Device failure

135
Q

What does the male sling procedure do?

A

Corrects stress urinary incontinence

136
Q

What is usually the cause of stress urinary incontinence in males?

A

Iatrogenic

137
Q

What are the iatrogenic of stress urinary incontinence in males?

A

Radical prostatectomy
Colorectal surgery
Radical pelvic radiotherapy

138
Q

What does the male sling procedure use?

A

Bone-anchored tape

139
Q

What is the problem with the male sling procedure?

A

It is an experimental/emerging treatment, and the long-term results are unknown