Control of Micturation

Question 1

what kind of motion moves urine through the ureters

Answer 1

peristaltic contraction

Question 2

what feature of ureters prevents reflux

Answer 2

they enter the bladder at an oblique angle and get compressed by bladder wall when it is full

Question 3

muscle of bladder contraction

Answer 3

detrusor muscle

Question 4

muscle type of internal urethral sphincter

Answer 4

smooth

Question 5

muscle type of external urethral sphincter

Answer 5

skeletal

Question 6

what type of muscle is the detrusor muscle

Answer 6

smooth

Question 7

a urethral obstruction will cause unilateral/bilateral kidney problems

Answer 7

bilateral

Question 8

what is the shape of a pressure vs volume in bladder graph like

Answer 8

has a little pressure increase around 100ml then plateaus till ~400ml where the pressure rapidly increases

Question 9

contraction state of sphincters at rest

Answer 9

both contracted

Question 10

broad process of micturation innervation

Answer 10

stretch receptors of bladder fire –>

1. parasympathetic neurons contract detrusor
2. sympathetic innervation that inhibits bladder contraction is inhibited
3. motor neurons stop firing to relax external sphincter

Question 11

what opens the internal sphincter

Answer 11

bladder contraction - it’s not really a sphincter, it is passively closed at rest

Question 12

what nerves contract the detrusor

Answer 12

S2-4

Question 13

nerves that inhibit bladder contraction

Answer 13

hypogastric (T12-L2)

Question 14

parasympathetic innervation of bladder

Answer 14

S2-4

Question 15

sympathetic innervation of bladder

Answer 15

T12-L2

Question 16

what stops semen refluxing into bladder

Answer 16

contraction of internal urethral sphincter

Question 17

innervation of external urethral sphincter

Answer 17

S2-4 (can make it constrict or relax)

Question 18

what the pudendal nerve roots

Answer 18

S2-4

Question 19

what prevents us from weeing ourselves when the stretch receptors get stimulated enough to trigger reflex

Answer 19

higher brain control

Question 20

at what bladder volume is the spinal reflex triggered

Answer 20

300-350ml

Question 21

actions from higher brain centre to delay peeing

Answer 21

1. inhibition of parasympathetic
2. stimulation of sympathetic
3. stimulation of somatic motorneurones

Question 22

actions from higher brain centres to voluntarily pee

Answer 22

1. stimulation of parasympathetic
2. inhibition of sympathetic
3. inhibition of somatic motorneurones

Question 23

how is remaining urine emptied from the female urethra

Answer 23

by gravity

Question 24

how is remaining urine emptied from the male urethra

Answer 24

by contractions of the bulbocavernosus muscle

Question 25

what other voluntary action may initiate micturation

Answer 25

relaxing the pelvic floor muscles - gives a downward tug on detrusor muscle