 The Ussing chamber provides a system to measure the transport of ions, nutrients, and drugs across various epithelial tissues, (although can generate false-negative results for lipophilic substances).It consists of two halves separated by the epithelia (sheet of mucosa or monolayer of epithelial cells grown on permeable supports).Epithelia are polar in nature, i.e., they have an apical or mucosal side and a basolateral or serosal side.