What is the main buffer system of the ECF?

a. Protein buffer system

b. Carbonic acid–bicarbonate ion buffer system

c. Phosphate buffer system

d. None of the above

Video transcript

Hey, everyone. Let's take a look at this question together. The following are the buffer systems of the extracellular fluid, except which is it? Answer choice. A the phosphate buffer system. Answer choice B the calcium buffer system. Answer choice C the bicarbonate buffer system or answer choice D the protein buffer system. Let's work this problem out together to try to figure out which of the following answer choices is a type of buffer system that is not present in the extracellular fluid. So in order to solve this question, we have to recall what we have learned about what buffer systems are present in the extracellular fluid or the ECF to determine which of the following answer choices is a buffer system that is not present. And we can recall that the extracellular fluid or the ECF has several buffer systems that help regulate Ph. And those buffer systems include the phosphate buffer system in which phosphate ions can act as buffers by accepting or releasing hydrogen ions to help regulate P as well as the bicarbonate buffer system, which the bicarbonate buffer system is the primary buffer system in the extracellular fluid. And involves irreversible reaction between bicarbonate ions and carbonic acid, which also helps maintain ph balance. And lastly, we know that one of the buffer systems of the extracellular fluid is the protein buffer system, particularly plasma proteins such as albumin, which acts as a buffer in the extracellular fluid where the carboxyl and the amino groups of the amino acids within the proteins and accept or donate hydrogen ions to help maintain that ph and looking at our answer choices, we see answer choice. A the phosphate buffer system. Answer choice C the bicarbonate buffer system and answer choice D the protein buffer system which are all present in the extracellular fluid. So answer choices. AC and D are all incorrect leaving us with only one remaining answer choice which is answer choice B the calcium buffer system. Since the calcium buffer system is not a recognized buffer system in the extracellular fluid. So answer choice B is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.