these results are consistant with the hypothesis that in the gall bladder the major barrier to ion permeation across the epithelium lies in 1 ) the tight junctions , when the lateral spaces are dilated , 2 ) the lateral spaces when the spaces are collapsed , and 3 ) a combination of both the spaces and the junctions when the spaces are reduced much below 0.5 mum .
C0014609
epithelium
C0242358
tight junctions