The peritoneal membrane is a semi-permeable membrane that lines the abdominal wall (parietal peritoneum) and covers the abdominal organs (visceral peritoneum). The membrane is a closed sac in males. The fallopian tubes and ovaries open into the peritoneal cavity in females. The size of the membrane approximates the body surface area (1-2 m2). There are about 100 cc of transudate that is contained in the cavity in normal individuals.
A. Blood Supply
The parietal peritoneum derives its blood supply from the arteries in the abdominal wall. This blood drains into the systemic circulation. The visceral peritoneum is supplied by blood from the mesenteric and coeliac arteries which drain into the portal vein.
Subdiaphragmatic lymphatics are responsible for 80% of the drainage from the peritoneal cavity. The drainage is then absorbed into the venous circulation through the right lymph duct and the left thoracic lymph duct. A balance of solutes and fluid in the interstitial tissue is maintained by absorption of fluid from the peritoneal cavity. The average lymphatic rate of absorption in the PD patient is 0.5-1.0 ml/min. Factors that affect the rate of absorption are respiratory rate, posture, and intra-abdominal pressure.