Most nutrients, such as glucose, are reabsorbed in the __________.

• A. distal convoluted tubule
• B. collecting duct
• C. proximal convoluted tubule
• D. loop of Henle

Answer: (C)

Verified step by step guidance

1. Understand the function of each part of the nephron: The nephron is the functional unit of the kidney, and its parts include the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct. Each part has a specific role in filtration, reabsorption, and secretion.
2. Learn about the proximal convoluted tubule: This is the first segment of the nephron after the glomerulus. It is responsible for reabsorbing most nutrients, including glucose, amino acids, and ions, as well as water. This reabsorption is crucial for maintaining homeostasis.
3. Compare the roles of other nephron segments: The loop of Henle primarily concentrates urine by reabsorbing water and salts. The distal convoluted tubule fine-tunes ion balance and pH, while the collecting duct is involved in water reabsorption under hormonal control (e.g., ADH). These segments do not reabsorb most nutrients like glucose.
4. Recognize the importance of glucose reabsorption: Glucose is a vital energy source for the body, and its reabsorption in the proximal convoluted tubule ensures it is not lost in urine. This process is facilitated by specific transport proteins.
5. Conclude that the proximal convoluted tubule is the correct answer: Based on its function, the proximal convoluted tubule is the site where most nutrients, including glucose, are reabsorbed. This distinguishes it from the other nephron segments listed in the problem.