Strong Fitness Bodybuilding Girl With Abdominal Six-pack Belly Muscles

- Accessory organs of the digestive tract: Liver, gallbladder and pancreas
- Urinary system: Kidneys and ureters - but technically located in retroperitoneum - outside peritoneal membrane
- Other organs: Spleen
Abdominal organs can be highly specialized in some animals. For example the stomach of ruminants (a suborder of mammals) is divided into four chambers - rumen, reticulum, omasum and abomasum.