Surface-volume relationships in endothelial and epithelial cells. Surface and Volume densities (Sv and Vv, respectively) are presented for endothelial (A, B) and epithelial (C, D) cellular compartments. Panels A and C refer to control condition (closed circles) and hypoxia exposure (open circles); the data for 3 and 5 hours of hypoxia were grouped together. Panels B and D refer to control condition (closed circles) and to cardiogenic edema (open triangles). The continuous lines in panels A and B correspond to the iso-surface conditions.