convoluted tubule convoluted tubule convoluted tubule is the compound of a metanephridium which is wrapped with capillaries. it is highly coiled so as to increase surface area for more effective reabsorption, which occurs in this part of the metanephridium. diagram of the uriniferous tubule and the blood vessels of the kidney. pc is the proximal convoluted tubule and idc is the distal convoluted tubule