Lecture 14 - Neurological Control Of Micturition Flashcards

1
Q

What is the muscle that makes up the wall of the bladder?

A

Detrusor muscle (smooth muscle)

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2
Q

What is the function of the Internal Urethral Sphincter?

What type of muscle makes it up?

A

Mainly prevents retrograde ejaculation

Smooth muscle

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3
Q

Where is theExternal Urethral Sphincter located ?

What type of muscle makes it up?

A

In the pelvic diaphragm

Made of skeletal muscle

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4
Q

Does the pressure of the bladder increase as volume increases?

Why?

A

Not immediately due to the detrusor relaxing so the bladder distends

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5
Q

What volume of urine leads to the pressure of urine to start rapidly increasing?

A

150ml

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6
Q

What is the volume of urine at which the voiding stage is stimulated?

A

500ml

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7
Q

What are the 2 phases in urodynamics?

A

Storage phase
Voiding phase

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8
Q

What is the storage phase of urodynamics?

A

When the bladder increases in volume with no appreciable change in pressure

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9
Q

What is the voiding phase?

A

Where the rhythmic contractions oof the detrusor muscle enable voiding

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10
Q

Go to the last slide and draw a pressure volume graph for the bladder:

A

See above slide for correct graph

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11
Q

What are the important spinal nerves in the control of micturition?

Look at the last slide at image 1 to label:

A

T10
L2

S2
S4

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12
Q

What is the importance of T10 to L2 in micturition?

A

The sympathetic region of the spinal cord involved in micturition

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13
Q

What is the importance of S2, S3 and S4?

A

S2, S3 and S4 keeps your Ps off the floor
Piss
Poo
Penis

Nerves for pelvic function

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14
Q

What type of nervous system control is the Storage phase generally under?

A

Sympathetic

S for storage + sympathetic

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15
Q

What type of nervous system control is the Voiding phase under?

A

Parasympathetic

Peeing = Parasympathetic

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16
Q

Where do the stretch receptors sensory neurones enter into the spinal cord?

Same for both storage and voiding phase

A

S2, S3 and S4

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17
Q

Once the sensory neurone from the bladder has entered into the spinal cord at the region of S2 - S4 in the STORAGE system what then happens?

A

Ascends and Synapses to a sympathetic neurone at level T10 - L2

Or continues to ascend to synapse at the cerebrum telling us how full the bladder is

18
Q

What 2 structures does the sympathetic neurone leaving the spinal cord synapse to?

(Storage phase)

A

Detrusor muscle

Internal Urethral sphincter

19
Q

What is the receptor that the sympathetic neurone that leads to the detrusor muscle of the bladder?

A

B3

20
Q

What affect does the sympathetics have on the detrusor muscle?

What receptor is this?

A

Inhibitory effect so prevents contraction of the detrusor muscle keeping the bladder relaxed so it can distend

B3

21
Q

What is the receptor that is found on the internal urethral sphincter that the sympathetic neurone leads to?

A

alpha 1

22
Q

What affect does the sympathetics have on the internal urethral sphincter? (Storage)

What receptor is involved?

A

Stimulates contraction of internal urethral sphincter

23
Q

What is the important somatic motor neurone that sends messages to the external urethral sphincter / pelvic floor?

A

Pudendal nerve

24
Q

What is the L centre?

A

Part of the storage part of urodynamics that helps prevent urination

L = Leave it for Later

25
Q

Where is the L centre located?

A

Brain stem

26
Q

What is nerve does the L centres neurone synapse to?

A

Pudendal nerve

27
Q

What part oof the body does the pudenal nerve go to innervate?

A

External Urethral sphincter

28
Q

What is the effect of the L centre synapsing to the pudendal nerve which innervates the external urethral sphincter?

A

Stimulates the contraction of the EUS maintaining continence

29
Q

What is the receptor that the pudendal nerve acts on at the External Urethral Sphincter?
(Stimulated by the L centre)

What is the neurotransmitter for this?

A

nAChR (Nicotinic acetylcholine receptors)

Ach

30
Q

What is the neurotransmitter for the sympathetic nerves for bladder control?

What receptors?

A

B3 (detrusor) = noradrenaline

A1 (IUS) = noradrenaline

31
Q

Go to the last slide and draw on all the structures relevant to the storage phase

A

Look at the slide above to check

Should have sensory neurones that synapse with sympathetics which lead to the detrusor and IUS
L centre leading to pudendal to EUS

32
Q

What type of neurone does the sensory neurone from the bladder synapse to at S2 - S4 in the voiding system?

A

Parasympathetic

33
Q

What does the parasympathetic neurone in the voiding system synapse to?

A

Detrusor muscle

34
Q

What affect does the parasympathetic nerves from the S2 - S4 region have on the detrusor muscle?

A

Stimulates detrusor muscle contraction

35
Q

What is the receptor and the neurotransmitter that the parasympathetic neurones act on in the detrusor muscle of the bladder?

A

M3 receptor

ACh

36
Q

What is the M centre?
Where is it located?
What is its function?

A

The micturition centre
In the brainstem
stimulates the parasympathetic neurone to stimulate the detrusor muscle to contract

37
Q

What are the extra neurones that connect directly to the parasympathetic neurones form the brain?

A

Inhibitory neurones inhibiting parasympathetics preventing voiding

38
Q

When is the M centre stimulated?

A

When the bladder stretches massively (sensory neurones)

Or when you decide that you want to urinate so neurones in cortex stimulate the M centre

Also neurones in cortex inhibiting M centre

39
Q

How are the M centre and the L centre connected?

A

The M centre synapses onto the L centre to inhibit the L centre

40
Q

Go the last slide and draw on all the relevant structures for the Voiding system:

A

Remember theres a connection between the M centre and L centre