Final answer:
The membranous peritoneal fold that attaches the intestines to the dorsal wall of the abdomen is called the mesentery, part of the visceral peritoneum.
Step-by-step explanation:
The membranous peritoneal fold that attaches the intestines to the dorsal wall of the abdomen is known as the mesentery. This structure is part of the visceral peritoneum, which envelopes the abdominal organs and holds them in place within the abdominal cavity. Within the mesentery, there are blood vessels, lymphatic vessels, and nerves which supply the intestines. Not all organs are attached via the mesentery; some, like the pancreas and portions of the large intestine, are considered retroperitoneal because they are located behind the peritoneum.