A 78-year-old man is brought to the hospital because of nausea and vomiting. On examination he appears dry, his abdomen is soft, and the JVP is not visible. His laboratory tests reveal hypernatremia and his calculated free water deficit is approximately 3 L. In what part of the normal kidney is most of the water reabsorbed from?
The largest volume of water is reabsorbed in the nephron at the proximal convolution. Maximally concentrated urine depends on ADH, which allows distal convoluted tubes and collecting ducts to become permeable to water.
collecting ducts
proximal tubule
distal tubule
ascending loop of Henle
Kidney