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.
A third part of the nephron is a collecting duct that drains urine from the tubule. Each tubule has three interconnected parts: the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule. The kidneys consist of an outer part (cortex) and an inner part (medulla). All glomeruli are located in the cortex, while tubules are located in both the cortex and the medulla. The urine drains from the collecting ducts of many thousands of nephrons into a cuplike structure (calix). Each kidney has several calices, all of which drain into a single central chamber (renal pelvis).