The esophagus brings food down to the stomach. The pyloric sphincter releases small amounts of partially digested food into the duodenum, which is the beginning of the small intestine.

The cecum is the first part of the large intestine. After traveling through the cecum, digested material travels up the ascending colon, past the hepatic flexure, through the transverse colon, past the splenic flexure, down the descending colon, and finally through the sigmoid colon.

The greater omentum is a large apron like fold of peritoneum that hangs from the greater curvature of the stomach in front of the small intestine. Once pass the small intestines, the greater omentum reflects on itself to reach the transverse colon. The lesser omentum connects the lesser curvature of the stomach to the liver. The greater omentum consists of visceral peritoneum.

The liver is a large organ located in the upper right quadrant (also known as the right hypochrondriac region) of the abdomen. It sits below the diaphragm and above the stomach and intestines.

The hypochondriac regions consist of the upper outer quadrants of the abdomen, lateral to the epigastric region. Specifically it consists of the area that is covered by the costal cartilage of the ribs. 

During the course of development the ascending colon is pushed against the posterior wall of the abdomen to become secondarily retroperitoneal. Other retroperitoneal organs include the descending colon, kidneys, adrenals, esophagus, ureters, pancreas (except tail), the second and third segments of the duodenum, the aorta/inferior vena cava, and the rectum. 

The spleen, transverse colon, and stomach are all intraperitoneal organs (located within the abdominal cavity and wrapped in peritoneum) .  

Retroperitoneal organs include the following: esophagus, adrenal glands, aorta/inferior vena cava, second and third parts of the duodenum, pancreas (except the tail), ureters, colon (ascending and descending portions), the kidneys, and the rectum.

The retroperitoneal space is an anatomical space within the abdomen but behind the peritoneum. Retroperitoneal organs should have peitoneum only at the anterior surface. These organs are not suspended by mesentery.

In the urinary system, the kidneys remove wastes from the blood and produce urine. The ureters are responsible for carrying the urine to be stored in the bladder. The urethra is responsible for draining urine from the bladder and conveying it out of the body.

The large intestine is responsible for absorbing water, salt, and electrolytes; when water is inadequately absorbed, diarrhea can result. The stomach is responsible for mixing food with mucus and gastric juice; it is not involved in absorption. The liver is responsible for producing bile, and the pancreas secretes enzymes to aid in digestion; these organs are also not involved with absorption.