Neuronal control of bladder

Question 1

Give the nerve supply, receptor and action of the parasympathetic innervation of the detrusor muscle

Answer 1

Pelvic nerve (S2-S4)
M3
Causes contraction

Question 2

Give the nerve supply, receptor and action of the sympathetic innervation of the detrusor muscle

Answer 2

Hypogastric nerve (T10-L2)
B3
Causes relaxation

Question 3

Give the nerve supply, receptor and action of the sympathetic innervation of the internal urethral sphincter

Answer 3

Hypogastric nerve (T10-L2)
A1
Causes contraction

Question 4

Give the nerve supply, receptor and action of the somatic innervation of the external urethral sphincter

Answer 4

Pudendal nerve (S2-S4)
Nicotinic receptors
Contraction

Question 5

Give the innervation for the bladder wall

Answer 5

Afferent stretch receptors

S2-S4

Question 6

Give the conditions that can arise as a result of nerve damage to the bladder innervation

Answer 6

Autonomous bladder
Automatic reflex bladder
Damage to the higher spinal cord

Question 7

Describe autonomous bladder

Answer 7

Damage to S2-S4
Affects:
1 - afferent stretch receptors don’t activate so cannot signal voiding
2 - damage to pudendal nerve means cannot contract detrusor
3 - damage to somatic innervation means cannot relax external urethral sphincter
Bladder capacity will continue to increase, but it cannot empty

Question 8

Describe automatic reflex bladder

Answer 8

Damage to spinal cord above the sacral level
Stretch receptors are activated and stimulate immediate voiding every 1-4 hours. This is due to a lack of descending voluntary inhibition. Also cannot contract the external urethral sphincter.

Question 9

Describe damage to the higher spinal cord

Answer 9

Damage to T10-L2
Lack of innervation via the hypogastric nerve, so do not have sympathetic outflow. - no detrusor relaxation- no contraction of internal urethral sphincter so have constant dribbling of urinePSNS and stretch receptors are intact, but the bladder never fills enough to activate them.