Micturition

Question 1

what makes up the internal urethral sphincter

Answer 1

thickening of the detrusor

Question 2

what makes up the external urethral sphincter

Answer 2

skeletal muscle from the pelvic floor

Question 3

what happens to the pressure with bladder filling

Answer 3

it doesn’t increase much as the bladder expands allowing for receptive relaxation

Question 4

what nervous system is the storage phase mostly controlled by

Answer 4

the sympathetic nervous system

Question 5

describe the sympathetic innervation to the bladder

Answer 5

stretch receptors in the detrusor send signals through the sensory neurone to S2-4. here it synapses with sympathetic neurones which travel to the detrusor to cause relaxation and to the internal urethral sphincter to cause contraction

Question 6

describe the somatic innervation involved in the control of micturition

Answer 6

neurones leaves the L centre in the pons and travel down the spinal cord and leave from S2,3,4 as the pudendal nerve -this causes contraction of the external sphincter

Question 7

what receptor does sympathetic innervation to the detrusor use

Answer 7

B3

Question 8

what receptor does sympathetic innervation to the internal sphincter use

Answer 8

alpha 1

Question 9

what receptor does somatic innervation to the external sphincter use

Answer 9

nAChR

Question 10

what nervous system is the void phase mostly controlled by

Answer 10

parasympathetic

Question 11

describe the parasympathetic innervation of the bladder

Answer 11

stretch receptors detect stretch and send signals through the sensory neurone to S2-4 of the spinal cord. here is synapses with parasympathetic nerves which cause contraction of the detrusor and activation of the M centre

Question 12

where is the M centre found

Answer 12

pons of the brainstem

Question 13

what does activation of the M centre cause

Answer 13

activation of the parasympathetics (overriding the inhibiting descending neurones)

Question 14

what normally inhibits micturition

Answer 14

sympathetics and the descending inhibiting neurone of the parasympathetic

Question 15

what affect does activation of the M centre have on the L centre

Answer 15

it inhibits the L centre causing sphincter relaxation

Question 16

describe the voluntary control of the void phase

Answer 16

cerebral neurones can cause activation or inhibition of the M centre under conscious control

Question 17

if there is a nerve lesion higher up in the spinal cord what effect will this have on micturition

Answer 17

will cause urinary incontinence as the descending neurones inhibiting the parasympathetics are lost

Question 18

if there is a nerve lesion lower in the spinal cord or caudal equina, what effect will this have on micturition

Answer 18

causes a stop to the void phase as the parasympathetic nerves are damaged - therefore the bladder will fill more and stretch - this will lead to overflow

Question 19

define urinary incontinence

Answer 19

involuntary leakage of urine

Question 20

what drugs can be used to treat urge UI

Answer 20

anticholinergics of M3 receptors, B3 agonists,

Question 21

what is urge UI

Answer 21

where there is urgent involuntary leakage

Question 22

what is stress UI

Answer 22

where leakage occur on exertion/coughing/sneezing