USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

What is the primary role of the Ureteric Bud in renal development?

1. Gives rise of ureter, pelvises, calyces, and collecting ducts

2. Interacts with metanephric mesenchyme

3. Restricts fluid along the proximal tubule

4. Causes glomerulotubular balance

The correct answer is: Gives rise of ureter, pelvises, calyces, and collecting ducts

The primary role of the Ureteric Bud in renal development is to give rise to the structures involved in urine collection and transport. Specifically, it develops into the ureter, renal pelvises, calyces, and the collecting ducts of the kidney. This development occurs in a highly regulated manner, where the ureteric bud branches out as it interacts with the nephric mesenchyme to promote the formation of the entire collecting system. The interaction between the Ureteric Bud and the metanephric mesenchyme is essential for the formation of functional nephrons; however, the Ureteric Bud itself is most directly responsible for forming the structures that collect and channel urine, making it a key player in the anatomy of the renal system. The other options either describe functions that are downstream effects of the kidney's structure or refer to processes not directly related to the primary role of the Ureteric Bud. Thus, the identification of the Ureteric Bud’s responsibility for developing the collecting system reinforces its central role in renal anatomy and function.