c.Bladder

• Urinary bladder


  • Situated immediately behind the pubic bones
  • Maximum capacity of about 500 ml
  • Empty bladder is pyramidal in shape, lies entirely within the pelvis in adults
• Apex


  Lies behind the upper margin of the symphysis pubis; connected to umbilicus by the median umbilical ligament (remains of urachus)
• Superolateral angles


  Joined by ureters
• Inferior angle


  Gives rise to urethra
• Neck


  Lies inferiorly and rests on the upper surface of Prostate (males); held in position by the Puboprostatic ligaments (males) / Pubovesical ligaments (females)
• Bladder


  • Muscular organ with smooth muscles - Detrusor
  • Transitional epithelium
  • Superior surface covered with peritoneum
  • Mucous membrane of the empty bladder is thrown into folds that disappears when the bladder is full
• Trigone


  Area of mucous membrane covering the internal surface of the base of the bladder with three openings - two from the ureters and one to the urethra
• Supporting Structures


  1. Ligaments

  2. Pubo-vesical

  3. Recto-vesical
• Pubo-vesical ligament


  Median pubovesical & lateral pubovesical ligament, between pubis and neck of bladder (male – pubo-prostatic ligament)
• Recto-vesical ligament


  From bladder to sides of rectum and sacrum
• Medial umbilical ligament


  Obliterated umbilical artery
• Median umbilical ligament


  Obliterated urachus
• Arterial supply to bladder

  • Superior vesical
  • Inferior vesical - from internal iliac
• Bladder veins


  • Vesical plexus to internal iliac
• Bladder nerves


  • Sympathetic: Upper lumbar nerves through hypogastric plexus - Inhibit contraction of detrussor muscle and stimulate closure of sphincter vesicae
  • Parasympathetic: Pelvic splanchnic w/c comes from 2nd, 3rd and 4th sacral nerves - Contraction of detrussor muscle and relaxes the sphincter vesical - Emptying the bladder
• Bladder lymphatic drainage


  • Internal and External Iliac nodes
• Ureteric bud/Metanephric diverticulum or duct


  Primordium of: 1. Ureter, 2. Renal Pelvis, 3. Renal calices, 4. Collecting tubules
• Metanephric tubule


  Forms the NEPHRON (Renal corpuscle, PCT, Loop of Henle, DCT)
• Development of the urinary bladder

  1. From the Vesical part of the UG sinus

  2. Initially the bladder is continuous with the Allantois which constricts to become the Urachus (represented by the Median umbilical cord in Adults)
• Cloaca


  Divisible into a Dorsal Rectum and Ventral Urogenital sinus thru Urorectal Septum
• Parts of the Urogenital sinus

  • Cranial Vesical part
  • Middle Pelvic part
  • Caudal Phallic part
• Fate of the Urogenital sinus parts

  • Vesical part - Urinary bladder
  • Pelvic part - Urethra in the bladder neck; Prostatic and Membranous parts in males and entire part in females plus the lower part of vagina