The renal pelvis is this entire section here. It's basically a funnel shaped cavity that collects the urine that is produced by the individual nephrons. And it directs that urine into a structure known as our ureter. The ureter is a structure that moves urine from the kidney and into the urinary bladder where it is stored before we secrete that to outside of our body. Now let's move on to our renal artery. So basically, the renal artery is the blood vessel system that brings the oxygenated blood, the blood filled with nutrients and also filled with the waste products that must be secreted by that kidney.