Morphologic evidence that rhe renal calyx and pelvis control ureteric activity in the rabbit.

Abstract

AbstractThe structure of the renal calyx, pelvis and upper ureter has been investigated in the adult rabbit. The methods employed for light microscopy were designed to demonstrate smooth muscle, cholinesterase and catecholamine‐containing nerves, elastic and collagenous fibers, and glycogen. Selected areas of the upper urinary tract were also examined using the electron microscope. The wall of the calyx and pelvis includes two layers of muscle cells the inner one of which appears to be continuous with the muscle coat of the ureter. The external layer extends across the renal pelvis from the calyx and ends abruptly in the pelvi‐ureteric region. In some regions cells from this layer run towards and intermingle with the muscle of the inner layer. The muscle cells forming the outer layer are associated with many adrenergic nerves which run in the connective tissue separating individual muscle cells. Numerous elastic fibrils are closely related to these cells which usually contain glycogen. In contrast, the muscle cells forming the inner layer of the pelvis and those of the upper ureter have a relatively poor innervation, are closely packed together without intervening connective tissue, and are usually devoid of glycogen. These observations provide structural evidence in support of the concept that specific regions of the renal calyx and pelvis influence and possbily control the activity of the ureter.