Visceral peritoneum

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Peritoneal cavity as seen in a parasagittal section.

The peritoneum is a continuous serous membrane. It consists of a layer of mesothelium and varying degrees of connective and adipose tissue. 

The peritoneum consists of two continuous layers. This includes the visceral peritoneum and the parietal peritoneum. The visceral peritoneum invests and envelopes the peritoneal viscera such as the stomach, liver, and small intestine. It also supports the organs of the abdomen and acts as a conduit for the passage of nerves, blood vessels, and lymphatics. There is also usually a small area where the visceral peritoneum folds back from the organ's surface. This creates double folds known as mesentery.

The visceral peritoneum shares a similar autonomic neurovascular supply with the organ's surface. This makes it insensitive to touch, heat and pain. However, it can be stimulated by stretching, for example urinary bladder and stomach distention, as well as by chemical irritation.

The function of the peritoneum is to secrete peritoneal fluid which helps lubricate viscera within the abdominal and pelvic cavities. This reduces the  friction between organs. This is important for dynamic organs like the intestines and the urinary bladder. Secondly, the peritoneum aids in the immune response, as the peritoneal fluid contains various immune cells.