Anatomy of urinary bladder, urethra and micturition

Question 1

How much urine triggers urinating

Answer 1

400-600ml

Question 2

Name of superior wall of bladder

Answer 2

Bladder apex

Question 3

What is the urethral sphincter?

Answer 3

Converge of bladder walls

Question 4

How is detrusor muscle controlled?

Answer 4

Autonomic innervation (not voluntarily controlled)

Question 5

What is the internal urethral sphincter?

Answer 5

Autonomically innervated, stops flow of urine into urethra to stop micturition

Question 6

Where is the prostate in relation to urethra?

Answer 6

Surrounds it

Question 7

Can we control external sphincter?

Answer 7

Yes it is striated

Question 8

What is the trigone?

Answer 8

Smooth muscle where ureters enter

Question 9

What makes the bladder wall tough?

Answer 9

Detrusor

Question 10

What is the uracus?

Answer 10

In embryo takes urine to be excreted but normally disappears, leaving median umbilical ligament

Question 11

Function of pubovesical ligament

Answer 11

From pubic bone, around bladder neck and back yo bone, holds neck rigid

Question 12

Another name for pubovesical ligament in men

Answer 12

Puboprostatic ligament

Question 13

What is transitional epithelium?

Answer 13

Cells in cube like structure, very organised, sits on lamina propria

Question 14

What is the serosa?

Answer 14

Flexible fascia

Question 15

Layers surrounding bladder, outwards to inwards

Answer 15

Perivesical fat
Serosa
Detrusor muscle
Submucosa
Lamina propria
Transitional epithelium

Question 16

How do ureters enter bladder?

Answer 16

Oblique fashion on posterior wall

Question 17

Where is the perineum?

Answer 17

Pubic symphysis to coccyx

Question 18

Which section of the pelvis is the bladder in?

Answer 18

Lesser

Question 19

Where does the pelvis divide?

Answer 19

Pelvis inlet - bordered by sacrum and pubic bones

Question 20

Function of medial umbilical ligament

Answer 20

Inserts into anterior abdominal wall, makes bladder tetrahedral

Question 21

Two pouches in females

Answer 21

Recto-uterine and utero-vosica;

Question 22

What is the sigmoid colon?

Answer 22

Large bowel that enters rectum

Question 23

Why is the lesser pelvis shaped like a funnel?

Answer 23

Levator ani

Question 24

What is the perineal membrane

Answer 24

Runs in anterior perineum between ischial tuberosities and pubic bone - halfway between perineal layers

Question 25

Layers of perineal

Answer 25

``` Deep pouch Perineal membrane Superficial pouch Deep fascia Superficial fascia ```

Question 26

Where does the aorta divide and what does it form

Answer 26

L4, forms common iliac arteries

Question 27

Which artery supplies pelvis?

Answer 27

Internal iliac

Question 28

Blood supply to bladder

Answer 28

Aorta - common iliac - internal iliac - vesical arteries

Question 29

Venous drainage of bladder

Answer 29

Vesical venous plexus Drains to internal iliac vein at multiple points Continuous with prostate/vaginal plexus

Question 30

Lymph drainage of bladder

Answer 30

- Deep abdominal and pelvic organs drain to lymph nodes around arteries - Superficial channels - lymph nodes around major veins - Bladder drains to internal, external iliac arteries

Question 31

Which plexus helps with micturition

Answer 31

Inferior hypogastric

Question 32

How do p/s neurones reach plexus

Answer 32

Pelvic splanchnic nerves

Question 33

How do sympathetic neurones reach plexus

Answer 33

Sacral splanchnic nerves

Question 34

Function of pudendal nerve

Answer 34

S2,3, innervates external urethral sphincter for voluntary contraction and inhibits micturition

Question 35

Which neurones inhibit micturition

Answer 35

Sympathetic

Question 36

Function of trigone in micturition

Answer 36

Stimulates visceral afferent nerves

Question 37

Where is the micturition centre

Answer 37

Pons

Question 38

What happens to bladder at rest?

Answer 38

At rest, visceral afferent nerves stimulate sacral splanchnic nerves to inferior hypogastric plexus - runs to detrusor muscle to relax it - internal urethral sphincter contracts to stop urine reaching urethra

Question 39

Spinal nerves parasympathetic - pelvic splanchnic nerves and inferior hypogastric plexus

Answer 39

S2-4

Question 40

Spinal nerves sympathetic - pelvic splanchnic nerves and inferior hypogastric plexus

Answer 40

T11-L2

Question 41

How does the urethra reach skin?

Answer 41

``` Anterior aperture of elevator ani Enters deep perineal pouch Enters superficial pouch In F enters vestibule In M enters glans ```

Question 42

Where is external urethral sphincter?

Answer 42

Deep pouch

Question 43

What is cystitis

Answer 43

Irritation of bladder wall

Question 44

Why are females more susceptible to UTIs

Answer 44

Urethra is only 4cm long

Question 45

What are Skene's glands?

Answer 45

Mucous glands wither side of urethra - homologous to prostate

Question 46

How is the urethra divided in men?

Answer 46

preprostatic, prostatic (dilatable, receives ejaculatory ducts), membranous (narrow, surrounded by external sphincter - catheters get resistance here), penile (receives bulbourethral glands, ends as navicular fossa)

Question 47

How does epithelium change along urethra?

Answer 47

transitional at beginning, then most is pseudostratified columnar, then stratified squamous (skin

Question 48

Which muscles help to clear urine from urethra?

Answer 48

Bulbospongiosus in M | Bulbocavernous in F

Question 49

Blood supply to urethra

Answer 49

M: P: Inferior vesical M: bulbourethral (from inf vesical) P: interior pudendal F: mix of vesical/vaginal/pudendal arteries

Question 50

Nervous supply of urethra

Answer 50

M: prostatic plexus, pudendal nerve F: vesical plexus, pudendal nerve

Question 51

Lymph drainage of urethra

Answer 51

M: anterior drains to inguinal lymph nodes, posterior to iliac lymph nodes F: iliac nodes

Question 52

Where is the narrowest part of the urethra in men?

Answer 52

Membranous

Question 53

Where will a catheter encounter resistance in men?

Answer 53

Prepubic angle | Infrapubic angle

Question 54

Suprapubic catheter

Answer 54

- Ultrasound to verify full bladder - Abdominal skin prepared and lidocaine injected into 2 centimetres above symphysis pubis - Risks: bowel perforation, bleeding, infection, enterovesical fistula - Indications: urethral injury, absolute urethral obstruction, long-term catheterisation - Method: direct puncture (mushroom catheter straightened with stylet and advanced into bladder, once catheter is confirmed within bladder, stylet removed) and seldinger technique (needle is inserted until urine aspirated, guidewire placed through needle into bladder and needle removed, dilator advanced over wire enlarging the tract. Dilator replaced with sheath, guidewire removed and catheter placed through sheath, which is peeled away. Balloon is inflated and catheter with drawn until tension felt, catheter connected to drainage system and secured)