Renal Vasculature of 2 Dasyurid Marsupials, Sminthopsis-Dolichura and S-Crassicaudata

Abstract

The renal vasculature of two dasyurid marsupials, Sminthopsis dolichura and S. crassicaudata, was examined using scanning electron microscopy of vascular corrosion casts of the kidney. Each species had a pair of unipapillary kidneys and the structural organisation of the major renal arterial vessels was similar to that of other placental mammals. The glomerulus of both species consisted of a network of dividing and anastomosing capillary loops. The glomeruli varied markedly in size, shape and complexity. Some afferent arterioles extended back towards the renal medulla, positioning the glomeruli closer to the cortico-medullary border. This placement of glomeruli may extend the loop of the nephron further into the medulla and thereby enhance counter-current water reabsorption and the final urine concentration. In both S. crassicaudata and S. dolichura, a dense mesh of numerous fine capillaries lined the wall of the renal pelvis adjacent to the inner medulla, with a unique configuration in that they were aligned perpendicular to the vasa recta. The function of these fine capillaries is unknown.

The Microanatomy of the Rectal Salt Gland of the Port Jackson Shark, <i>Heterodontus portusjacksoni</i> (Meyer) (Heterodontidae): Suggestions for a Counter-Current Exchange System

“…The dorsal aorta was traced to the anterior supply of the rectal salt gland. Vascular casts were produced in situ by displacing blood from the rectal salt gland and replacing this with methacrylate resin [O'Shea et al, 1993;Brooker et al, 1995]. A single lumen, medical grade polyethylene tube (internal diameter 1.00 mm and external diameter 1.50 mm) was heated to produce a funnel at the anterior end, which allowed the tubing to be secured in place with a surgical suture.…”

The physiology of the honey possum, Tarsipes rostratus, a small marsupial with a suite of highly specialised characters: a review

“…Gross morphological features in the opossum D. virginiana and a number of species of West Australian kangaroos and wallabies in relation to renal concentrating ability were reported in the 1970s (Yadav 1979;Purohit 1974;Krause et al 1979) and variations in renal medullary thickness (RMT) were related to environmental aridity in 25 species of dasyurids by Brooker and Withers (1994). An allometric study by Beuchat (1990) relating variations in RMT and urine osmolality to body mass in mammals included 25 marsupial species and a detailed study of renal vasculature in two dasyurids, Sminthopsis dolichura and S. crassicaudata by Brooker et al (1995) complement early observations by Reid andMcDonald (1967) andPak Poy (1957).…”