Which of the following is considered the functional unit of the kidney?

• A. Mitochondrion
• B. Nephron
• C. Lysosome
• D. Glomerulus

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the question by identifying the key term 'functional unit of the kidney.' This refers to the smallest structure within the kidney that performs its essential functions.
2. Step 2: Recall the primary function of the kidney, which is to filter blood, remove waste products, and regulate water and electrolyte balance. The structure responsible for these tasks is the nephron.
3. Step 3: Break down the nephron's components: it includes the glomerulus (a network of capillaries for filtration), Bowman's capsule, proximal tubule, loop of Henle, distal tubule, and collecting duct. Together, these structures perform filtration, reabsorption, secretion, and excretion.
4. Step 4: Compare the options provided: Mitochondrion and lysosome are organelles found in cells and are not specific to kidney function. The glomerulus is part of the nephron but not the entire functional unit. The nephron is the correct answer as it encompasses all processes necessary for kidney function.
5. Step 5: Conclude that the nephron is the functional unit of the kidney because it is the smallest structure capable of performing all the kidney's essential functions.