The luminal aspect of intrarenal arteries and veins in the rat as revealed by scanning electron microscopy

Abstract

The luminal aspect of intrarenal arteries and veins in the rat has been investigated by scanning electron microscopy (SEM). The endothelium of the intrarenal arteries consists of spindle-shaped cells and forms longitudinally running ridges which correlate with the folding pattern of the underlying internal elastic lamina. Intraarterial "cushions" were found at the origins of afferent arterioles from arcuate arteries and along the entire course of interlobular arteries. The intrarenal veins are made up of a thin, extensively fenestrated epithelium equal to that of peritubular capillaries. The outer aspect of the endothelium contacts adjacent tubules as closely as the capillaries proper. Thereby, the luminal aspect of the veins exhibits a striking "tubule relief" created by the underlying tubules. This wall structure of the intrarenal veins suggest that diameter and shape of the veins are probably highly dependent on the surrounding interstitial pressure.

Intrarenal oxygenation: unique challenges and the biophysical basis of homeostasis

“…Mathematical models also support its existence (14,45,104,110). It is driven by the AV PO 2 difference and facilitated by the close anatomical association of arteries and veins, as occurs most strikingly in the kidney (31,32,80,84). Nordsletten et al (80) Fig.…”

RENAL PREGLOMERULAR ARTERIAL–VENOUS O2 SHUNTING IS A STRUCTURAL ANTI‐OXIDANT DEFENCE MECHANISM OF THE RENAL CORTEX

“…7 Shurek et al have suggested that the efficiency of renal O 2 shunting may be facilitated by the unique arrangement of the intrarenal vasculature, with the interlobular arteries being in close contact with, and partially surrounded by, the interlobular veins. 7 Frank and Kriz have described the interlobular veins as being thin walled with many fenestrations, similar to the wall structure of capillaries 11 (Fig. 1).…”

“…they receive a high proportion of the cardiac output compared with other organs). 30 However, unlike the mammalian kidney, in which the incoming arterial and outgoing venous vasculature are closely associated, 11 the afferent and efferent vessels of most non-mammalian vertebrate kidneys, such as those of birds, reptiles and amphibians, are not in close proximity to each other. 31 Thus, arterial-venous oxygen shunting is unlikely to be important in the kidneys of these animals.…”

“…Indeed, they described them as '… overlying the arteries like a veil', a description that accords with efficient arterial-venous diffusional O 2 exchange. 11 Schurek et al suggested the arcuate and interlobar vessels may also be involved in gas exchange, because these arteries and veins run in close juxtaposition. Figure 1 shows this close relationship in arcuate vessels, with the artery being partially surrounded by the vein.…”

From tubular sublimate nephropathy via urinary concentrating mechanism to glomerular disease—Wilhelm Kriz’s contribution to modern nephrology

“…Kriz put much effort into the structural analysis of the vascular and lymphatic system of the kidney in his initial work. Before the functional background of multiple exchange pathways constituting the function of the renal concentrating mechanism, the arrangement of arterial and venous vessel types in the particular kidney zones was pioneering work, allowing understanding of the complex relation between tubular segments, interstitium, and blood vessels in the renal medulla [6,18,39,41,44,45,68,85]. Analyses across several species revealed the structural correlates of wet vs. arid habitats with animals displaying short vs. long papillae and further parenchymal specificities.…”