The renal pelvis or pyelum the funnel-like dilated proximal part of the ureter in the kidney. In humans, the renal pelvis is the point of convergence of two or three major calyces. Each  renal papilla is surrounded by a branch of the renal pelvis called a caylx. The major function of the renal pelvis is to act as a funnel for urine flowing to the ureter.
Renal pelvis is located inside the kidney. The function of renal pelvis is collect the urine and send it to ureter. It acts like a funnel to dilute the urine and its shape is also like a funnel.