Histological Features of the Renal Collecting System in Pig (Sus scrofa domesticus)

Abstract

Histological features of pig Renal Collecting System (RCS) revealed collecting tubules lined by simple cuboidal epithelium which opened into papillary ducts with tall cuboidal epithelium. These ducts were opened into minor calyx on the edge of renal papilla. Minor and major calyces were lined by 6 to 8 cell thick transitional epithelium. Tunica muscularis was thicker in major calyx than in minor calyx. Transitional epithelium of renal pelvis consisted 10 to 16 cell layers. Three ill-defined layers of smooth muscle amongst moderate bundles of collagen fibres were seen in tunica muscularis. Long mucosal folds were seen projecting into lumen of ureter whose number, length and width decreased from proximal to distal parts. Transitional epithelium lined the ureteral mucosa. Its thickness increased in proximal to distal direction. Tunica muscularis with inner circular and outer longitudinal smooth muscle layers was seen and thick tunica adventitia consisted collagen fibres, muscular arteries, veins and abundant adipose tissue. Mild reaction for PAS-AB was noticed in sub-epithelial zone of ureteral mucosa and a negligible reaction for PAS was seen on surface portion of mucosal folds of pig ureter and calices in this study