Control of Bladder Emptying

Question 1

What is the renal pelvis?

Answer 1

Urine flows from each of the renal calyces into a funnel-shaped dilation of the upper ureter called the renal pelvis

Question 2

What cells control peristalsis in the ureters?

Answer 2

atypical smooth muscle cells

they propagate peristaltic waves down the ureter

Question 3

WHat is the scientific term for kidney stones?

Answer 3

nephrolithiasis or ueterolithiasis

Question 4

What are the treatments for kidney stones?

Answer 4

percutaneous nephrostomy

extracorporeal shock wave lithotripsy

Question 5

WHat is the empty volume of the bladder?

What volume can it expand to?

Answer 5

<100ml when empty

typical maximum of 500-1000ml

Question 6

Does urine change from when its produced to when its excreted?

Answer 6

Essentially unchanged

expect for some signalling molecules and cells orginiating from the urothelium

Question 7

What the the urinary bladder wall consist of?

Answer 7

urothelium
lamina proproa
deterusor smooth muscle
serosa`

Question 8

Describe the structure and function of the urothelium

Answer 8

High resistance tight junctions between the cells greately reduce permeability through the wall
The urine-facing surface has specialised cells called umbrella cells
Once thought of as a passive barrier, there is now more research focusing of singlalling from the urothelial cells to the lamina propria and detruspr, sensing the contrents of the stpred uromed and affecting the urinary frequency

Question 9

Describe the structure and function of the lamina propria

Answer 9

contains blood vessesl, lymphatics, nerves and intersistal cells of cajal in a connective tissue mesh
many nerve terminals in this area are sensory and involved in detecting chemical and mechanical stimuli

Question 10

What do interstitial cells of cajal do?

Answer 10

unknown function

thought to mediate signalling between the urothelium and the detrusor smooth muscle without involving nerves

Question 11

What is the strucytre and fuction of the detrusor muscle?

Answer 11

smooth cells run in bundles, irregular basket weave pattern
inneverated by autonomic nerves
parasympathetic dominant M3 muscarinin receptors to cause contraction
Sympathetic nerves release NAd onto beta3 adrenoreceptors to cause relaxation

Question 12

What are the general principles of continence and voiding?

Answer 12

Continence
- low pressure reservoir for storage of waste products
- continually active sphincter to prevent leakage
Voiding
- relaxation of sphincters
- increase pressure in reservoir

Question 13

What 4 things do you need for continence and voiding?

Answer 13

• sensory mechanisms to inform about filling
• higher control centres for voluntary voiding
• reflex pathways to generate voiding
• the right muscles to do it

Question 14

How are the layers of the urethra different to that of the bladder?

Answer 14

it has smooth muscle AND skeletal muscle
under voluntary control
somatic nerves, ACh receptors

Question 15

What are the layer of the urethra?

Answer 15

urothelium 
lamina propria
longitudinal smooth muscle
circular smooth muscle
striated muscle

Question 16

Describe the nerves involved in maintaining continence

Answer 16

somsatic system active - keeps striated system contacted

• Sympathetic system active - constricts smooth muscle sphincters
• Parasympathetic system - inactive ``

Question 17

Describe the nerves involved in voiding

Answer 17

`Somatic and sympathetic switch off - sphincters relax

Parasympathetic system activated - storage element walls contract

Question 18

Draw storage reflex

Answer 18

see lecture

Question 19

Draw voiding reflex

Answer 19

see lecture

Question 20

When is urinary continence a problem>

Answer 20

UTI - chemical stimuli increase bladder activity and hence urge to void
Spinal cord disorder - spinal cord injury and MS
Stroke
Pelvic floor injury (e.g. following childbirth)
Detrusor overactviity (leading to overactive baldder syndrome) common with age, outflow obstruction
Atonic bladder - many be secondary to autonomic neuropathy

Question 21

Describe stress incontinence

Answer 21

Weakness in muscles of vaginal wall / pelvic floor. Greatly reduces resistance of the external urethral sphincter
Any increase in abdominal pressure e.g. coughing can cause the leakage of urine

Question 22

What are the treatments for stress incontinence?

Answer 22

conservative management
OAB drugs
surgery to support prolapse

Question 23

What is the pharmacological management of overactive bladder?

Answer 23

antimuscarinc durgs - useful in short to medium term but show tolerance
botulinum toxin - very useful, but difficult to use and requires repeated/ongoing treatment
B3 adrenorecprot agonists
others (don’t need to know)

Question 24

What is the treatment for urinary outflow obstruction?

Answer 24

surgical - transurethral resection of the prostate
medical - alpha1 anatgonists, partly through relaxation of the smooth muscle of the prostate
5 alpha reductas inhibitprs: reduce hypertrophy