In the kidney, what is the primary function of the renal pelvis?

• A. Secretes hormones that regulate red blood cell production and blood pressure
• B. Reabsorbs most water and solutes from the filtrate
• C. Filters blood plasma to form the initial filtrate
• D. Collects urine from the major calyces and funnels it into the ureter

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the anatomy of the kidney, focusing on the flow of urine from the nephrons to the ureter. The nephron produces filtrate, which eventually becomes urine.
2. Step 2: Identify the role of the renal pelvis in this flow. The renal pelvis is a funnel-shaped structure located at the center of the kidney.
3. Step 3: Recognize that the renal pelvis collects urine from the major calyces, which themselves collect urine from the minor calyces connected to the nephrons.
4. Step 4: Note that the renal pelvis does not perform filtration, reabsorption, or hormone secretion; instead, it serves as a passageway for urine.
5. Step 5: Conclude that the primary function of the renal pelvis is to collect urine from the major calyces and funnel it into the ureter for transport to the bladder.