In kidney anatomy, what is a renal papilla?

• A. The funnel-shaped collecting region that receives urine from the major calyces and becomes the ureter
• B. The outer granular region of the kidney that contains renal corpuscles and proximal and distal convoluted tubules
• C. A branch of the renal artery that runs between renal pyramids to supply the cortex
• D. The apex of a renal pyramid that projects into a minor calyx and drains urine from papillary ducts

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the structure of the kidney, which includes the cortex (outer region), medulla (inner region), renal pyramids, calyces, and the ureter.
2. Step 2: Identify the renal pyramid as a cone-shaped tissue mass in the medulla, which contains the loops of Henle and collecting ducts.
3. Step 3: Recognize that the apex (tip) of each renal pyramid is called the renal papilla.
4. Step 4: Know that the renal papilla projects into a minor calyx, which is a small funnel-shaped structure that collects urine from the papillary ducts.
5. Step 5: Understand that urine flows from the papillary ducts at the renal papilla into the minor calyx, then into major calyces, and eventually into the ureter for excretion.