Multiple choice

Paracetamol causes acute and chronic renal tubules failure in humans. From the following statements, select the false statement concerning the renal tubules in kidneys.

  1. The major changes in tubular fluid composition are made in the proximal tubules.

  2. The proximal tubules substantially increases the concentration of urine.

  3. Part of the loop of henle is permeable to water.

  4. The vasa recta are blood vessels.

  5. The walls of the tubules are made up of epithelial cells.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The osmolality of filtered fluid entering the proximal tubule from the glomerulus is essentially that of plasma from which it is produced. Reabsorption in the proximal tubule is iso-osmotic, which means that the osmolality of the tubular fluid does not change because solutes and water are removed together in the same ratio at which they are present in the tubules. For this reason, the concentration of urine (i.e. its osmolality) in the proximal tubule is not altered.