A MORPHOLOGICAL STUDY AND DIAGNOTIC ULTRASONOGRAPHY OF ASIAN ELEPHANT KIDNEY

Abstract

Kidneys from a forty year old, female, Asian elephant (Elephas maximus) were subjected to a gross anatomical study (measurements, dissection, parasagittal sections and photography), histological examination, and ultrasonographic images. The kidney had an elliptical to ovoid shape with a size of 32x21x12 centimeters (length, width, and thickness). It was of multilobar or multipyramidal type, composed of 8 lobes, closely placed and separated by interlobar septae, some of which were perforated by minor interruptions. Each lobe had one calyx, connected to its secondary infundibulum which converged into two primary infundibula, one each on end of the renal sinus. The 2 primary infundibula were joined at the hilus to become the ureter which tranversed caudally to
the urinary bladder. A major branch of the renal artery penetrated the renal capsule and coursed along the corticomedullary junction along side to the interlobar artery that supplied blood to that particular lobe. Histologically, the renal capsule consisted of two layers; the outer a thin connective tissue layer that was densely and irregularly arranged, the inner was thick and composed of 2-3 layers of multidirectional small smooth muscle
bundles. The renal cortex was easily identified by the presence of renal corpuscles. The medullary rays were noticeable and structural differences between the proximal and distal convoluted tubules were observed. The area cribosa is formed not only from the outlets of the terminal collecting ducts, but also conjoined to the tubus maximus which was at the center of the papilla. Structural differences in the epithelium of the walls of the calyx and the secondary and primary infundibula were also observed. Ultrasonographic images revealed the renal capsule, interlobar septum, calyx, and secondary infundibulum as hyperechoic lines. The renal cortex appeared more echogenic than the medulla, which appeared as a hypoechoic triangular area.