Isotopes when written out are common nouns, and should begin with the uncapitalized element name, followed by a hyphen (not an em dash or en dash) and then the mass number. Examples are carbon-14 and uranium-235.
The central region of the kidney contains the renal pelvis, which is located in the renal sinus, and is continuous with the ureter. The renal pelvis is a large cavity that collects the urine as it is produced. The periphery of the renal pelvis is interrupted by cuplike projections called calyces.
The major calices then converge into a funnel-like cavity called the renal pelvis. The renal pelvis, which is attached to the indented side of the kidney anatomy (hilum), extends into the ureter. The ureter is a long narrow duct (tube) that conveys urine from the kidneys to the urinary bladder.