Organ
Renal papilla
The pyramid tip opening into a minor calyx
High-yield
The papilla is the junction where intrarenal collecting ducts empty into the calyceal lumen.
Overview
At each papillary tip, converging collecting ducts discharge through multiple openings into a minor calyx. This perforated surface is the area cribrosa. Adjacent pyramids may fuse, producing a compound papilla and a different calyceal configuration.
Reference facts
- Location
- At the apex of a renal pyramid, projecting into the surrounding minor calyx.
- Parts
- An area cribrosa with variable numbers of papillary-duct openings; the duct epithelium meets the urothelial collecting-system lining.
- Blood supply
- Medullary microvessels support tissue in a relatively low-oxygen environment.
- Innervation
- Visceral renal and ureteric pathways transmit pain associated with collecting-system distension rather than a uniquely papillary sensory territory.
- Function
- Delivers urine from papillary ducts into the calyceal lumen.
Mnemonic
Follow the exit: pyramid tip, papillary openings, then the calyceal cup.
Clinical correlation
Necrotic papillary tissue may detach and obstruct the collecting tract, causing pain or hydronephrosis. Imaging can show papillary cavities or filling defects; these findings require interpretation alongside causes such as diabetes, sickling, infection and analgesic injury.
Frequently asked questions
Where is the renal papilla located?
At the apex of a renal pyramid, projecting into the surrounding minor calyx.
What does the renal papilla do?
Delivers urine from papillary ducts into the calyceal lumen.
What are the parts of the renal papilla?
An area cribrosa with variable numbers of papillary-duct openings; the duct epithelium meets the urothelial collecting-system lining.
What is the blood supply of the renal papilla?
The renal papilla is supplied by the medullary microvessels support tissue in a relatively low-oxygen environment.