Fig. 1

This sketch depicts a nephron (A), the smallest functional unit of the kidney. It consists of the bowman capsule and the tubule system. The tubule system can be divided in the proximal and distal tubule, the loope of Henle and the collecting duct. Panel B provides in an insight into the proximal tubule. The tubule epithelial cells are attached to the basement membrane, and behind it is the interstitial space, containing matrix proteins and fibroblasts. Panel B shows the effect of extracellular acidosis on proximal tubule cells and fibroblasts while enabling cellular crosstalk between these cells. Panels C and D show the impact of extracellular acidosis on proximal tubule cells (C) and fibroblasts (D) without cellular crosstalk