The distal convoluted tubules of adjacent nephrons opens into a common collecting duct or tubule in the papilla of the medulla or of individual medullary pyramids. Several adjacent collecting tubules converge to open into a common short and thick duct of Bellini. All ducts of Bellini, then open at the tips of the papilla or papillae into the pelvis.
Ureters narrow tubes with a thick, muscular wall having an outer fibrous coat, a middle muscular coat and inner mucous membrane.
The middle part of medulla of kidney projects towards hilus in the form of a conical renal papilla.
In duodenum are found intestinal glands (Brunner's gland) that secrete a little enzyme and mucus.