Lecture 17: Pelvic Viscera 1

Question 1

What is a sphincter?

Answer 1

Localised muscle thickening around wall of tubular viscus to control passage of contents and prevent reflux

Question 2

What is an anatomical/functional sphincter?

Answer 2

Anatomical - clearly defined muscle ring

Functional - walls of tube act as a sphincter when exposed to increased pressure

Question 3

How long is the ureter and how long is the pelvic ureter?

Answer 3

25cm

12.5cm

Question 4

What is the intramural part of the ureter?

Answer 4

Part of the ureter that enters the bladder - acts as a functional sphincter

Question 5

How is urine passed from the ureter to the bladder?

Answer 5

Peristalsis, ureters made up of circular and smooth muscle

Question 6

Where do the ureters enter the bladder

Answer 6

Posterolaterally through urethral orifices at top of trigone

Question 7

What happens as the bladder fills?

Answer 7

Pressure increases, causes walls of ureters to close on themselves to prevent reflux of urine

Question 8

What is the blood supply to the ureters?

Answer 8

Take blood supply from region they are at. Blood vessels in the abdomen pass medially and in pelvis pass laterally

Question 9

What crosses the ureter in males and females?

Answer 9

Vas deferens and uterine artery

Question 10

What happens if the ureters get distended?

Answer 10

Because the ureter is smooth muscle it will spasm and fire sensory nerve impulses to CNS - interpreted as being from skin - pain referred to rib, groin or external genitals (T11-L1)

Question 11

What % of ureters are bifid and what does this cause?

Answer 11

1% - more frequent UTIs

Question 12

How common are pelvic horseshoe kidneys and why do they occur?

Answer 12

0.2%
As body elongates kidney moves - they may stay joined and cannot meet their destination due to major midline vessels - kidney left in pelvic cavity

Question 13

Where does the bladder sit?

Answer 13

In the pelvis on the vagina (support)

Question 14

What covers the superior surface of the bladder and what does this form?

Answer 14

Peritoneal coat - forms rectovescial and uterovesical pouches

Question 15

What part of the bladder is continuos with the urethra?

Answer 15

Neck

Question 16

What is the middle fold of peritoneum remnant of and what is it now?

Answer 16

Urachus - median umbilical ligament

Question 17

What happens if the median umbilical ligament remains patent in adulthood?

Answer 17

Urine from bellybutton

Question 18

How does the bladder position change?

Answer 18

In abdomen in children - pelvis isn’t large enough until 5/6 to accommodate bladder

Question 19

What is the inside of the bladder like?

Answer 19

Detrusorr muscle - lots of rug to expand - trigone on posterior wall that retains its shape and position always

Question 20

What is the base of the trigone?

Answer 20

Intrauteric bar

Question 21

What sphincter is present in only males (function?) and when may this be damaged?

Answer 21

Internal urethral sphincter - stops reflux of semen during ejaculation - damaged in TERP when cleaning out the prostate

Question 22

What are the steps of the micturition reflex?

Answer 22

1. Reflex arc involving parasympathetic fibres via S2-4 to cause contraction of detrusor muscle
2. Relaxation of (involuntary) internal urethral sphincter – sympathetics to T12-L1
3. Relaxation of (voluntary) external urethral sphincter and levator ani (S2-4) via pudendal nerve
4. Raised intra-abdominal pressure
5. Urination

Question 23

What is a suprapubic puncture?

Answer 23

Penetrating pelvic wall using a catheter - bladder volume must be high so bladder is above pelvic brim

Question 24

How is the urethra different in males and females?

Answer 24

F - short, straight, easy to catheterise, exits just below clitoris
M - 20cm, bends, difficult to catheterise

Question 25

What are the 3 parts of the male urethra?

Answer 25

Postatic, membranous, spongy/penile

Question 26

What gender is urinary incontinence more common in and why?

Answer 26

Females - absence of internal urethral sphincter

Question 27

What part of the GI tract is in the pelvis?

Answer 27

Descending colon, sigmoid colon and rectum

Question 28

What spinal segments does the rectum exist at?

Answer 28

S3 to tip of coccyx

Question 29

What are the features of the rectum?

Answer 29

Muscle coat, no mesentery, distal 1/3 dilated as ampulla, transverse rectal folds for storage of faeces, peritoneum on aspects of upper 2/3, surrounded by rectal fascia that may prevent transmission of cancer cells