Abdomen, Pelvis & Perineum
Collecting part of kidney of derived from (AIPG-2013)
Pg. 1308; Gray's Anatomy (40th Ed.)
During the fifth week of gestation, the mesonephric duct develops an out-pouching, the ureteric bud, near its attachment to the cloaca.
This bud, also called the metanephrogenic diverticulum, grows posteriorly and towards the head of the embryo. The elongated stalk of the ureteric bud, the metanephric duct, later forms the ureter.
As the cranial end of the bud extends into the intermediate mesoderm (Metanephros), it undergoes a series of branching to form the collecting duct system of the kidney. It also forms the major and minor calyces and the renal pelvis.
The portion of the intermediate mesoderm in contact with the tips of the branching ureteric bud is known as the metanephrogenic blastema. Signals released from the ureteric bud induce the differentiation of the metanephrogenic blastema into the renal tubules (Nephrons of kidney).
As the renal tubules grow, they come into contact and join with connecting tubules of the collecting duct system, forming a continuous passage for flow from the renal tubule to the collecting duct.