What regions of the kidneys unite to form the renal pelvis? A. Renal columns B. Major calyx C. Minor calyx D. Renal pyramids

To answer the question, let's analyze the options:

1. Renal Columns: These are extensions of the cortex between the renal pyramids and do not directly contribute to the formation of the renal pelvis.

2. Major Calyx: This is a larger collecting area that drains multiple minor calyxes and eventually contributes to the renal pelvis.

3. Minor Calyx: This is a small cup-like structure that collects urine from the renal pyramids and merges to form the major calyxes, which in turn form the renal pelvis.

4. Renal Pyramids: These are the triangular sections of the kidney that contain the nephrons and drain urine into the minor calyxes, but do not unite to form the renal pelvis themselves.

Final Answer

B. Major calyx is the most direct answer, as the major calyces combine to form the renal pelvis, although minor calyces lead into them.