An investigation into the fine structure of the ligated rat ureter

The normal structure of the ureter of the rat is described and compared with the results of earlier work. Research on arteries left in situ stimulated morphological investigation of the ligated ureter proximally and distally to the ligature. As in ligated blood vessels, an increase in modified muscle cells with accompanying increase in connective tissue (particularly proximally to the ligature) occurs in the ureter. In association with quantitative changes, qualitative changes in the formation of collagen and in the arrangement of fibrils were found, although not so marked as in arteries subjected to "load failure". During a comparison of the ureteric walls on either side of a ligature intracellular collagen was found. The results of earlier work on ligated ureters are discussed, together with the present findings. The reactions of ureteric and arterial walls subjected to similar "load failures" are compared. Qualitative changes in the intercellular substance are considered in connection with the findings in cases of pathological processes in the walls of blood vessels. Several possibilities are suggested with regard to the interpretation of the intracellular collagen.