When sodium is actively transported from tubular cells to the interstitial fluid,
A)no energy is needed.
B)glucose and amino acids are countertransported at the same time.
C)Na+ concentration gradient is established between the tubule lumen and tubule cell.
D)water is countertransported by carrier molecules.
E)water is secreted.

Question

Quizplus · Accepted Answer

Active transport of sodium from tubular cells to the interstitial fluid establishes a concentration gradient where the Na+ concentration is lower in the tubule lumen than in the tubule cell. This gradient drives the passive reabsorption of sodium in the nephron. Glucose and amino acids are co-transported with sodium, but no energy is needed for water to follow sodium reabsorption via osmosis, and water is not counter-transported.

When Sodium Is Actively Transported from Tubular Cells to the Interstitial