Fill in the blanks: The kidneys produce  _____ urine when the osmolarity of the body's fluids increases. They produce _____urine when the osmolarity of the body's fluids decreases.

Video transcript

Welcome back, everyone. Here's our next question. Under what circumstances does the late distal tubule and collecting system produce concentrated urine? A when sodium reabsorption is decreased. B when potassium secretion is enhanced, see when water reabsorption is increased or d when glucose levels are elevated. So let's recall what it means to have something be reabsorbed or secreted. It's reabsorbed, it's removed from the filtrate that's going to become in the urine and taken back into the body. When it's secreted, the body is pushing it into the filtrate to be eliminated. So with that in mind, what will produce concentrated urine? So lower water content, that's kind of simplistic but helping us focus in on what we're looking for. So choi says when sodium reabsorption is decreased, but we should remember that water follows sodium. So if the body is reabsorbing less sodium, it also will be reabsorbing less water. So that would mean that the urine has more water as less as being reabsorbed by the body. So that will produce more dilute urine if sodium resorption is decreased. So choice A cannot be our correct answer. Um Just a little note on that, an example of this would be through the action of the A NP hormone. This causes less sodium reabsorption by inhibiting sodium reabsorption. It prevents water reabsorption and therefore causes a greater dilution of urine. So it's sort of the counteract actor to the A DH hormone. So it was just good to keep those two straight. Choice B when potassium secretion is enhanced. Well, this is not going to be our answer because potassium secretion is important to maintaining electrolyte balance. But isn't really a part of the dilution or concentration of urine. So that's why choice B won't be our answer. Choice C says when water reabsorption is increased. Well, if the body is reabsorbing more water, as we said, that results in lower water content in the urine and thus more concentrated. So choice C will be a circumstance that causes the production of concentrated urine. Then finally, we have choice d when glucose levels are elevated. So, of course, normally urine doesn't have glucose in it, your body should reabsorb all of it. But if something happens, you have too much glucose. Like someone with uncontrolled diabetes, elevated glucose levels. So glucose making it through into the filtrate means that water, we essentially follow the glucose into the filtrate by osmosis. Higher water content will result in more dilute urine. So choice D also not correct. So once again, the circumstances under which the late distal tubule and collecting system produce concentrated urine is choice C when water reabsorption is increased. See you in the next video.