Fig. 3.

Diagram of vasa recta architecture in the outer zone of the IM. UT-B-positive (shaded light, nonfenestrated) DVR descends along the corticopapillary axis. UT-B-positive segment overlaps (small bracket) with PV-1 (shaded dark, fenestrated) and is continuous with a descending PV-1-positive, UT-B-negative DVR (large bracket). This PV-1-positive segment is continuous with AVR₁, which lie within the CD cluster (intracluster region) (8). AVR₁ connect to AVR₂ in vascular bundles of the intercluster region. Arrows denote blood flow direction. AVR₁, PV-1-positive intracluster AVR and interconnecting capillaries that do abut CDs; AVR₂, ascending PV-1-positive intercluster vessels that do not abut CDs, and do or do not abut DVR.