Final answer:
The double peritoneal fold of the mesentery consists of the visceral peritoneum and the parietal peritoneum. Within these folds are blood vessels, lymphatic vessels, and nerves that innervate the organs and supply adjacent structures.
Step-by-step explanation:
The double peritoneal fold of the mesentery consists of the visceral peritoneum and the parietal peritoneum. The visceral peritoneum envelops the abdominal organs, while the parietal peritoneum lines the abdominal wall. Within these folds, you can find blood vessels, lymphatic vessels, and nerves that innervate the organs and supply adjacent structures.