USMLE Step 1 Renal Physiology 1 Review 58 21 Loop of Henle Reabsorption

USMLE Step 1 Renal Physiology 1 Review 58 21 Loop of Henle Reabsorption

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Play USMLE Audio MP3 58 21 Loop of Henle Reabsorption Below

Begin 58 21 Loop of Henle Reabsorption Transcription

What does the thin descending limb of the Loop of Henle reabsorb?

  • Water.

And how does it do this?

  • The thin descending limb reabsorbs water by passive reabsorption.

And what is this due to? The answer starts with MH.

  • Medullar hypertonicity.

What two substances are primarily responsible for the hypertonicity for the renal medulla?

  • Sodium chloride and urea.

List three substances actively reabsorbed by the thick ascending limb of the Loop of Henle. I’ll cue you with the first letter of each.

First, C.

  • Chloride.

Second, P.

  • Potassium.

Third, S.

  • Sodium.

What percent of sodium reabsorption does this account for?

  • 20%.

And there is induced reabsorption of what two substances in the thick ascending limb? They start with C and M.

  • Calcium and magnesium.

Student doctor, please pause the tape and summarize what we’ve discussed about tubular transport in the thin descending limb of the Loop of Henle and the thick ascending limb of Henle.

  • The thin descending limb passively reabsorbs water. This happens because of the hypertonicity of the medulla which is primarily due to sodium chloride and urea. The three substances actively reabsorbed by the thick ascending limb of the Loop of Henle are chloride, potassium, and sodium. This accounts for 20% of the sodium reabsorption. There is also induced reabsorption of calcium and magnesium in the thick ascending limb.

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