Lecture 14 - Neurological Control Of Micturition Flashcards
What is the muscle that makes up the wall of the bladder?
Detrusor muscle (smooth muscle)
What is the function of the Internal Urethral Sphincter?
What type of muscle makes it up?
Mainly prevents retrograde ejaculation
Smooth muscle
Where is theExternal Urethral Sphincter located ?
What type of muscle makes it up?
In the pelvic diaphragm
Made of skeletal muscle
Does the pressure of the bladder increase as volume increases?
Why?
Not immediately due to the detrusor relaxing so the bladder distends
What volume of urine leads to the pressure of urine to start rapidly increasing?
150ml
What is the volume of urine at which the voiding stage is stimulated?
500ml
What are the 2 phases in urodynamics?
Storage phase
Voiding phase
What is the storage phase of urodynamics?
When the bladder increases in volume with no appreciable change in pressure
What is the voiding phase?
Where the rhythmic contractions oof the detrusor muscle enable voiding
Go to the last slide and draw a pressure volume graph for the bladder:
See above slide for correct graph
What are the important spinal nerves in the control of micturition?
Look at the last slide at image 1 to label:
T10
L2
S2
S4
What is the importance of T10 to L2 in micturition?
The sympathetic region of the spinal cord involved in micturition
What is the importance of S2, S3 and S4?
S2, S3 and S4 keeps your Ps off the floor
Piss
Poo
Penis
Nerves for pelvic function
What type of nervous system control is the Storage phase generally under?
Sympathetic
S for storage + sympathetic
What type of nervous system control is the Voiding phase under?
Parasympathetic
Peeing = Parasympathetic
Where do the stretch receptors sensory neurones enter into the spinal cord?
Same for both storage and voiding phase
S2, S3 and S4
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?
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
What 2 structures does the sympathetic neurone leaving the spinal cord synapse to?
(Storage phase)
Detrusor muscle
Internal Urethral sphincter
What is the receptor that the sympathetic neurone that leads to the detrusor muscle of the bladder?
B3
What affect does the sympathetics have on the detrusor muscle?
What receptor is this?
Inhibitory effect so prevents contraction of the detrusor muscle keeping the bladder relaxed so it can distend
B3
What is the receptor that is found on the internal urethral sphincter that the sympathetic neurone leads to?
alpha 1
What affect does the sympathetics have on the internal urethral sphincter? (Storage)
What receptor is involved?
Stimulates contraction of internal urethral sphincter
What is the important somatic motor neurone that sends messages to the external urethral sphincter / pelvic floor?
Pudendal nerve
What is the L centre?
Part of the storage part of urodynamics that helps prevent urination
L = Leave it for Later
