Micturition & Assessment of renal function

Question 1

what is the nerve supply that controls micturition?

Answer 1

inhibition of sympathetic innervation to internal sphincter - (T10-L2)
activation of parasympathetic innervation via pelvic nerve (S2,3,4) to internal sphincter
inhibition of somatic tonic inhibitory action to external sphincter via S2,3,4 (pedundal nerve)

Question 2

what is type of tissue makes up the bladder?

Answer 2

smooth muscle detrusor

Question 3

how does the ureters enter the bladder and why is this of clinical significance?

Answer 3

enter the bladder at an angle (obliquely) in order to prevent urine reflux

Question 4

what is the name of the triangle portion of the posterior wall of the bladder?

Answer 4

trigone

Question 5

what is measurement is used to assess renal function and what is it?

Answer 5

creatinine
it is a breakdown product muscle - creatine
it determines the amount of plasma that if filtered and therefore GFR

Question 6

what is the gold standard test to measure GFR and how does it do this?

Answer 6

inulin clearance
can measure plasma clearance as it is a direct correlation to the amount of plasma that is filtered as inulin isn’t reabsorbed or secreted at all

Question 7

what is the normal GFR?

what is the difference in females compared to males?

Answer 7

125 ml/min

women have 10% lower GFR

Question 8

what factors may affect creatine levels when there is no pathology?

Answer 8

athletes (a lot of muscle = a lot of creatine byproduct)
drugs; aspirin decreases creatinine
dietary intake i.e. creatine supplements

Question 9

what is the clearance of urea compared to inulin and why?

Answer 9

urea is less than inulin because some of the urea is reabsorbed in the collecting duct to concentrate urine

Question 10

what is the clearance of penicillin compared to inulin and why?

Answer 10

clearance of penicillin is greater than inulin because it is filtered and secreted
(no inulin is secreted from the blood stream)

Question 11

what is PAH clearance?

Answer 11

measurement of renal plasma flow (RPF)

measures all the plasma flowing through the kidneys at a given time

Question 12

what is the normal value for PAH?

Answer 12

600mls/min

Question 13

how does urine flow through the ureters into the bladder?

Answer 13

via peristaltic contractions

Question 14

what is the normal volume of urine excretion per day?

Answer 14

750 - 2500mls/day

Question 15

what nerve innervation is responsible for the increased contraction of the bladder when the pressure increases?

Answer 15

parasympathetic innervation via pelvis nerves S2,3,4

Question 16

what nerve innervation is responsible for closing the internal urethral sphincter?

Answer 16

sympathetic innervation via hypogastric nerves T10-L1

inhibit bladder contraction

Question 17

apart from closing the internal urethral sphincter, what is the main function of the hypogastric nerves ?

Answer 17

prevent reflux of semen into the bladder after ejaculation L1-L3

Question 18

after urination, how does the remaining of the male urethra empty?

Answer 18

by contractions of the bulbocavernous muscle

Question 19

what is the normal creatinine?

Answer 19

125mls/min