Multiple choice

The kidneys excrete about 15% of the filtered potassium load of 10 mEq/kg per day. Which among the following statements concerning potassium is true?

  1. Potassium is the major extracellular ion.

  2. Within cells, the concentration of potassium is lower than that of sodium.

  3. Potassium excretion is regulated by altering potassium secretion.

  4. The 3Na+/2K+ ATPase pumps potassium out of the cells.

  5. Selected cells have potassium channels.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Potassium is freely filtered and then most of the filtered potassium is reabsorbed. Potassium excretion is then controlled by the secretion of potassium by the principal cells in the collecting ducts.

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