Which of the following mechanisms is/are used by the kidneys to regulate the pH of the blood? Circle all that apply.

a. Hydrogen ions are secreted from the proximal and distal tubules and the collecting system.

b. Hydrogen ions are reabsorbed from the nephron loop.

c. New bicarbonate ions are formed from glutamine and carbon dioxide in the interstitial fluid that enters proximal tubule cells.

d. Bicarbonate ions can be secreted.

e. Bicarbonate ions are reabsorbed directly from the filtrate.

Video transcript

Hey, everyone. Let's take a look at this question together. Renal regulation of blood. Ph is concerned with the following, except which is it answer choice. A excretion of hydrogen ions back into the bloodstream reabsorption of bicarbonate in the proximal tubule. Answer choice C it secretes hydrogen ions into the urine or answer choice. D none of the above. Let's work this problem out together to try to figure out which of the following answer choices is renal regulation of blood ph, not concerned with. So, in order to solve this question, we have to recall what we have learned about renal regulation of blood Ph to determine which of the following answer choices is it not concerned with? And we can recall that the kidneys have two main ways to maintain that acid based balance, which includes that their cells reabsorbed by carbonate from the urine back to the blood and the kidneys secrete hydrogen ions into the urine. So the way that the kidneys maintain that acid based balance is that they adjust the amounts that are reabsorbed or secreted. In order to balance that, Ph still looking at our answer choices related to renal regulation of blood ph we know that their cells reabsorb bicarbonate ions from the urine back to the blood which occurs in the proximal tubule. So, answer choice B can not be the correct answer. And we also know that they secrete hydrogen ions into the urine. Which means that answer choice C is also incorrect. As both answer choice B and C are ways that the kidneys maintain acid based balance. So answer choice D cannot be the correct answer either. So answer choice. A excretion of hydrogen ions back into the blood stream must be the correct answer. As we know that the kidneys secrete hydrogen ions into the urine and reabsorbed by carbonate in the proximal tubule which goes back into the bloodstream. So they do not excrete hydrogen ions back into the bloodstream. Making answer choice. A correct answer. I hope you found this video to be helpful. Thank you and goodbye.