Which structure is the structural and functional unit of the kidney?

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

Answer: (A)

Verified step by step guidance

1. Understand the question is asking for the structural and functional unit of the kidney, which means the smallest part that performs all the essential functions of the kidney.
2. Recall that the kidney's main functions include filtering blood, removing waste, and regulating fluid and electrolyte balance.
3. Identify the nephron as the microscopic structure responsible for these functions, including filtration, reabsorption, and secretion.
4. Recognize that other options like the renal capsule, ureter, and renal pelvis are parts of the kidney but serve different roles: the renal capsule is a protective layer, the ureter transports urine, and the renal pelvis collects urine.
5. Conclude that the nephron is the correct answer because it is the basic unit that carries out the kidney's essential functions.