RT Book, Section A1 Seshadri, Anupamaa A1 Rangel, Erika A2 Doherty, Gerard M. SR Print(0) ID 1171278152 T1 Peritoneal Cavity T2 Current Diagnosis & Treatment: Surgery, 15e YR 2020 FD 2020 PB McGraw Hill LLC PP New York, NY SN 9781260122213 LK accessmedicine.mhmedical.com/content.aspx?aid=1171278152 RD 2024/10/13 AB The peritoneum is a thin serous membrane that lines the peritoneal cavity. It is the largest serous surface layer in the human body, and its surface area is comparable to the skin. The structure is made up of a single flat layer of mesothelial cells, rich in microvilli. Beneath the mesothelium are a basement membrane and a loose collagen network containing vascularized connective tissue with scattered fibroblasts and macrophages. Normally there is between 5 and 20 mL of free peritoneal fluid. This can vary in women, peaking after ovulation. Normal peritoneal fluid has a specific gravity of less than 1.016, protein concentration of less than 3 g/dL, pH between 7.5 and 8, and white blood cell count (WBC) of less than 3000/µL.