Which structure is the functional unit of the kidney?

• A. Ureter
• B. Renal artery
• C. Renal pelvis
• D. Nephron

Answer: (D)

Verified step by step guidance

1. Understand that the kidney is composed of various structures, each with a specific role in the process of urine formation and filtration.
2. Identify the main structures listed: the ureter (which transports urine from the kidney to the bladder), the renal artery (which supplies blood to the kidney), and the renal pelvis (which collects urine before it moves to the ureter).
3. Recall that the functional unit of an organ is the smallest structure capable of performing all the functions of that organ independently.
4. Recognize that the nephron is the microscopic structure within the kidney responsible for filtering blood, reabsorbing needed substances, and forming urine.
5. Conclude that since the nephron carries out the essential functions of the kidney, it is considered the functional unit of the kidney.