Electron microscopic observations on the juxtamedullary efferent arterioles and Arteriolae rectae in kidneys of rats.

Abstract

Efferent arterioles leaving juxtamedullary glomeruli in the kidneys of rats have a media comprized of a layer of closely packed smooth muscle cells. This muscle coat continues along the length of the efferent arterioles and arteriolae rectae to a level deep in the outer medullary zone, where smooth muscle cells are gradually replaced by pericytes characteristic of the non-muscular arterial vasa recta.