L7.1 Pelvic viscera

Question 1

Unpaired viscera

Answer 1

• develop in midline (Some may migrate to non-midline)
• Receive NS from both sides of spinal cord → Refer pain back to midline

Question 2

Paired viscera

Answer 2

• Develop bilaterally
• NS & BS form each side
• Refer pain to same side

Question 3

2 types of sphincters

Answer 3

• Tubular viscera has sphincter guarding entrance & exit

1. Anatomical
   
   • Smooth circular muscles - within body cavity
   • Skeletal muscles - Near exit of body
2. Functional
   
   • Wall of tube acts as sphincter (e.g. bladder & ureter)

Question 4

Ureter

Answer 4

• 25cm (pelvic part 12.5cm)
• Serosa → Muscularis (has circular & longitudinal S.M) → Mucosa
• Passes urine down via peristalsis
• Pierce bladder POS-LATerally via urethral orifice
  
  • Intramural part = part passing through the wall
• Increase pressure in bladder as it fills → closes ureter at the intramural part (FUNCTIONAL sphincter)
  
  • Prevents reflux of urine back to ureter/kidney (may occur when there is damage)

Question 5

BS to the ureter

Answer 5

• Extensive along the length
  
  • Coming from medial (in abdominal part)
  • Coming from lateral (in pelvic part)

Question 6

Things crossing the ureter

Answer 6

• Males: Crossed only by vas deferens
• Females: Uterine A

Question 7

Uteric calculi

Answer 7

• Stones → may lodge at sites of narrowing → spasm → passes N impulses
• Referred pain: T11-L1 (follow sym) dermatomes

Question 8

Renal and uteric anomalies

Answer 8

• Semi/Bifid ureters (1%)
  
  • Increase association with urinary tract infections (Much narrower)
• Pelvic (horseshoe) kidney (0.2%)
  
  • Normally: Starts off in midline → post development → Changes with body elongation
    
    • May be obstructed by big vessels (i.e IMA)
  • In pelvic kidney: Kidney left within pelvic cavity & not in ab cavity

Question 9

Bladder

Answer 9

• Rests on vagina (if vag prolapse → decrease support)
• Increasing bladder volume → pushes peritoneal coat up (which coats rectum, vagina & bladder)
• Neck is continous with urethra (needs support of vag & L.Ani)
  
  • Lack of support leads to incontinence
• Median umbilical ligament (remnant of aracheus) - ascends from apex
  
  • Open in fetus → urine from bladder to umbilicus
  • If it remains open in adults → urine may leak from belly button
• In children <6yo, position is in the abdomen

Question 10

Median umbilical ligament

Answer 10

• Median umbilical ligament (remnant of aracheus) - ascends from apex
  
  • Open in fetus → urine from bladder to umbilicus
  • If it remains open in adults → urine may leak from belly button

Question 11

Internal urethral sphincter

Answer 11

• Internal urethral sphincter ONLY in males
  
  • Primarily to prevent backflow of semen from prostatic urethra
  • TURP process (removal of prostate) → may damage sphincter → seminal regurgitation in bladder

Question 12

Walls of the bladder

Answer 12

• Mucosa (detrusor)
  
  • Large SA → allows expansion to accommodate increase in urine
• Trigone (where ureters come in)
  
  • Interuteric bar lies in b/w the 2 orifice
  • Is a layer of SM which is different from detrusor (cannot be stretched)
• Walls allow motility/expansion of bladder

Question 13

What occurs when critical point of storage is reached?

Answer 13

• Critical point of storage → reflexes triggered → micturition

Question 14

Micturition reflex

Answer 14

• Receptor = bladder → full → afferent → CNS (Pudendal N = S2-4) → efferent → effector = bladder → contraction of detrusor muscles
• Relaxation of external urethral sphincter (Males and females)
  
  • Voluntary
• Relaxation of internal urethral sphincter (Males)
  
  • Involuntary - by SNS T12-L1
• Increase abdominal pressure
• Pudendal N & L.Ani required for micturition

Question 15

What is the suprapubic puncture

Answer 15

• Used when urine remains in bladder → may become infected
• But puncture causes danger in penetrating other structures

Question 16

Urethra

Answer 16

• Females: Short, opens ANT to vag (below clitoris)
• Males:
  
  • Pre-prostatic (intramural part)
  • Prostatic (through prostate)
  • Membranous (Through ex urethral sphincter, in deep perineal pouch)
  • Spongy (on corpus spongiosum)
  • Navicular fossa = dilated opening at the glans

Question 17

Urethral caterterisation

Answer 17

• Simple for females short
• Longer for males and has to be navigated

Question 18

Urinary incontinence

Answer 18

• Incontinence results from N damage or less of mechanical support
• Artificial urinary sphincter: Could use device to regulate time for urinary expulsion

Question 19

Sigmoid colon

Answer 19

• Etends from D.colon to rectum at S3
• Sigmoid mesocolon → allows mobility
• Muscle layers externally for peristalsis

Question 20

Rectum

Answer 20

• 3rd part of sacrum to tip of coccyx
• Transverse rectal folds → storage of feces in rectum
  
  • Allows air passing through without expelling contents
• Surrounded by rectal fascia
• Ampulla = dilated 3rd distal part

Question 21

Pelvic peritoneum

Answer 21

• Peritoneum on SUP A-L upper 2/3 of rectum
• Uterus
• Urinary bladder (SUP)
• → goes to ANT ab wall