Bladder Anatomy and Physiology

Question 1

What is the normal capacity of the bladder?

Answer 1

400-500mL

Question 2

What ligaments hold the bladder?

Answer 2

1. Bladder neck by
   - puboprostatic ligament in male
   - pubovesical ligament in female
2. Median umbilical ligament

Question 3

What is the remnant of the allantois

Answer 3

obliterated urachus

Question 4

What is the allantois?

Answer 4

In embryo, the allantois is a canal that drains the urinary bladder of the fetus and that joins and runs within the umbilical cord.

Question 5

What type of epitheium is in the bladder?

Answer 5

Transitional epithelium

Question 6

What type of muscle is the bladder made off?

Answer 6

Detrusor muscle

Question 7

What are the layers of the bladder muscle?

Answer 7

Detrusor muscle

Longitudinal
Circular
Spiral

Question 8

How thick is the bladder muscle?

Answer 8

Detrusor muscle

5mm

Question 9

Weakening in which sphincter causes incontinence?

Answer 9

Pre-prostatic sphincter (bladder neck) males

Question 10

What is the arterial blood supply to the bladder?

Answer 10

2 arteries:

1. internal vesicle artery
2. external vesicle artery

arise from:
internal iliac arteries from the anterior trunk

Question 11

Venous drainage of bladder?

Answer 11

Rich plexus of veins that ultimately empties into the internal iliac veins

Question 12

Lymphatic drainage of bladder

Answer 12

Lymph nodes at:

• vesicle
• internal iliac
• external iliac
• common iliac lymph nodes

Question 13

What structures sense bladder filling?

Answer 13

Afferent parasympathetic neurons > spinal cord > pontine and micturition centres

Question 14

Where does the efferent motor bladder innervation arise from?

Answer 14

S2-4

S2 3 4 keeps the shit of the floor

Question 15

What is the main centre for micturition?

Answer 15

Pontine micturition centre in the dorsolateral pons

Question 16

Where is the sacral micturition centre?

Answer 16

1. Intermediolateral nucleus: PS S2-4 –> bladder

2. Onuf’s nucleus: PS S2-4 –> urethra

Question 17

Which nerve is responsible for urine retention?

Answer 17

Hypogastric (sympathetic nerve)

Question 18

Which nerve is responsible for micturition (voiding)?

Answer 18

Pelvic nerve (parasympathetic)

Question 19

Which nerve detects stretch?

Answer 19

Sensory pelvic nerve (afferent)
- sends impulses to S2-S4
from stretch receptors on the detrusor muscle

Question 20

Which nervous systems are involved in bladder efferent innervation?

Answer 20

1. Parasympatheic
2. Sympathetic
3. Somatic

Question 21

Is the pelvic nerve under voluntary of involuntary action?

Answer 21

involuntary

Question 22

What nervous system does the pelvic nerve that causes contract belong to?

Answer 22

Parasympathetic

Question 23

What neurotransmitter and to which receptor does the pelvic nerve act on?

Answer 23

S2 to S4
Pelvic nerve to detrusor muscle
Involuntary
Parasympathetic
Released ACh
Acts on M3R
Causes relaxation

Question 24

What effects does the hypogastric nerve have on the bladder?

Answer 24

Hypogastric 
Sympathetic
- detrusor muscle: relaxation (b3R)
- internal sphincter: contraction (a1R)
Noradrenaline

Question 25

Where does the hypogastric nerve arise from?

Answer 25

T10-L2

Question 26

What nerve controls the external urethral sphincter?

Answer 26

Pudendal nerve

Question 27

Where does the pudendal nerve arise from?

Answer 27

Onuf's nucleus Anterior horn S2-S4

Question 28

What nerve is blocked during labour and what does this cause?

Answer 28

Female pudendal nerve block | Causes relaxation of external sphincter

Question 29

What is the action of the pudendal nerve?

Answer 29

voluntary contraction of the external urethral sphincter

Question 30

What nerve is used when we're forcibly stopping ourselves from peeing?

Answer 30

Pudendal nerve on external urethral sphincter

Question 31

What neurotransmitter and receptor does the pudendal nerve act via?

Answer 31

ACh | Nicotinic receptor

Question 32

In BPH what drug can be used and whats it MOA?

Answer 32

Tamsulosin alpha1-R blocker in neck of the bladder of the hypogastric nerve

Question 33

Where is the sacral micturition centre located?

Answer 33

Spinal cord S2-S4 Intermediolateral grey area

Question 34

Where is Onuf's nucleus located?

Answer 34

Spinal cord S2-4 Anterior horn

Question 35

What is the relevance of Onuf's nucleus?

Answer 35

Continence Acts via pudendal nerve nerve - somatic voluntary contraction

Question 36

What is the relevance of the sacral micturition centre

Answer 36

Voiding Acts on the pelvic nerve - parasympathetic contraction

Question 37

Which spinal cord injury results in incontinence?

Answer 37

Sacral spinal cord injury

Question 38

Which nerve(s) are stimulated during retention?

Answer 38

1. Hypogastric T10-L2 - Relaxation of detrusor muscle b3R NA - Contraction of internal sphincter a1R NA - Sympathetic 2. Pudendal (Onuf's nucleus) - contraction of external sphincter NR ACh - Somatic

Question 39

Which nerve(s) are stimulated during micturition?

Answer 39

Pelvic (sacral micturition centre) S2-S4

Question 40

How do we maintain a urine flow?

Answer 40

1. Pelvic sensory neurons keep firing to sacral micturition centre (S2-S4) - inferomediolateral grey area 2. this stimulates the pelvic parasympathetic pelvic nerve to keep firing ACh at the M3R 3. This maintains contraction of the detrusor muscle and thus urination

Question 41

What happens during spinal shock?

Answer 41

Period of reduced excitability at and below spinal cord injury

Question 42

What is autonomic dysreflexia?

Answer 42

SCI T6 or higher | - exaggerated SNS activity