Explain why and how total body sodium content, ECF volume, and blood pressure are jointly regulated.

Video transcript

Welcome back, everyone. Here's our next problem which of the following hormones or mechanisms is or are involved in the regulation of sodium content and blood pressure of the body choice. A renin angiotensin aldosterone system or Raasb insulin, C, oxytocin D atrial natriuretic peptide or A NP E, both A and D or F all of the above. So basically, we've got four different hormones or mechanisms and we have the possibility of more than one correct answer. So let's just work our way through each of these to a, the RAAS system. Down here at the bottom involves the release of Rennin from the kidneys, which leads to the pro production of angiotensinogen, which then leads to the production of angiotensin one, which is converted to angiotensin two. That's where its name comes from. Angiotensin two is a vaso constrictor. So it causes blood pressure to increase and it also stimulates the release of Aldo and aldosterone causes sodium and water reso reabsorption to increase in the kidneys. And that of course will cause blood volume but BV to increase, which causes blood pressure to increase. So, the ras system definitely is involved in the regulation of sodium content and blood pressure. So we're just gonna put a dot here, since we have the potential of more than one correct answer, then we'll look at Choice B. Choice B is insulin and insulin is not involved in either sodium content regulation or blood pressure regulation. It's involved in the regulation of blood sugar. So that's not one of our answers. So we'll go ahead and cross that out. Then we move on to choice. C. Choice C also is something different, not related to blood pressure. Oxytocin stimulates uterine contractions as the beginning of the labor process. And it's also sometimes called the love hormone because it promotes sexual arousal and bonding and feelings of affection uh between uh uh mother and child, between individuals. So it has different roles but is not part of the regulation of blood pressure. Then finally, our fourth hormone here or a mechanism atrial nature peptide or a NP. And this also is definitely involved in an opposite way than RAAS. This is, I'll put a NP down at the bottom here. This is released by the atria cells in response to stretching and what would cause a stretching of atrial walls that would be increased blood pressure, increased blood volume. As a result, it decreases the reabsorption of sodium and water by the kidneys which causes blood volume to decrease and blood pressure to decrease. So, a NP stimulates the reverse mechanism of the RAAS system in bringing blood pressure and blood volume down, but it is definitely involved in regulation. So that's correct. So we see choice f all of the above is not correct since B and C are incorrect. But our answer here here will be choice E both A and D because the ras system and the A NP uh hormone are both involved in regulating sodium content and blood pressure. See you in the next video.