Figure 2.

The organization of the renal arterial tree and its various components. (A) A composite low-power micrograph of two CRAs and their afferent arterioles depicts the high variability in the arterial organization. The asterisks point to afferent arterioles organized as pairs, and the arrows point to connecting arteries branching from the CRA. The box encloses an afferent arteriolar pair that is looked at closer in panel B. (B) The vascular layers comprising this pair of arterioles includes the axially oriented cells of the endothelium and radially oriented smooth muscle cell layer. The box encloses a section of the vessel that is analyzed further in panel C. (C) Shown are the myoendothelial junctions (MEJs) protruding from ECs toward the VSMCs. This panel also illustrates the presence of MEGJs comprised of Cxs present at MEJs. Gap junctions enable depolarizing TGF signals to transmit upstream of the afferent arteriole to neighboring afferent arterioles and into the larger artery, where similar signals from other afferent arterioles can interact to regulate vascular resistance. Panel (A) reprinted from ref. 10, with permission.