mouse TS23
  embryo
  cavities and their linings
  limb
  mesenchyme
  vertebral axis muscle system
  organ system
  gland
  visceral organ
  alimentary system
  oral region
  gut
  anal region
  anal canal
  external sphincter
  internal sphincter
  liver and biliary system
  renal/urinary system
  reproductive system
  respiratory system
  nervous system
  integumental system
  sensory organ
  cardiovascular system
  skeleton
  tail
  extraembryonic component