My god this has got to be the best, and probably the only explanation on UA-cam, which actually explains the counter current system of the Vasa Recta, and not just the Loop of Henle! Thank you so much Pete!!!!!!!!!!!
Nope. Blood flows from the AFFERENT arteriole to the GLOMERULUS to the EFFERENT arteriole to the PERITUBULAR CAPILLARY (PTC). The VASA RECTA is a specialized section of the PTC for juxtamedullary nephrons. Therefore, the EFFERENT arteriole immediately precedes the VASA RECTA.
You are amazing. The way you narrate and explain is clear to understand yet retains all the complexity needed for a high level of education. Thank you.
To me, this video did the job! Thanks a lot:-) I think some of the comments below fail to appreciate that this video focuses exclusively on the role of the vasa recta.. the glomerulus and the origin of the CCM and all that, you should look for elsewhere guys!
Vasa recta just means straight (=recta) arteries of the kidney. It is another system next to the loop of henle which primarily allows for perfusion of the kidney - so basically its a source of blood supply to the kidney + helps maintain the countercurrent mechanism. Hope that helps.
So i can conclude that: 1. The medulla need blood supply (vasa recta) to provide oxygen and reabsorb solute (send to circulation) 2. But if all the solute is taken away, it will disrupt the osmotic gradient 3. So in order to prevent this, counter current arrangement is used (to minimize solute taken away from the medullary interstitium) 4. A small portion solute is taken away to circulation (but most are released back into the interstitium at ascending limb) 5. This way, the osmotic gradient is conserved
Green Rocket--all correct, nice summary! It's worth mentioning that point #4 (i.e., some solute carried away) has an important role for regulating salt/water handling in the kidneys. A variety of regulatory systems can impact the rate of renal blood flow, ultimately modulating the amount of solute that is carried away by circulation (with its attendant effect on the osmotic gradient).
@YATIN PATEL. No because this is the vasa recta which is more distal to the glomerulus. Afferent ---> glomerulus ----> efferent ---> peritubular capillaries or vasa recta --> branch of renal vein
Amazing explanation. I am wondering how does the increased blood flow into vasa recta diminish the gradient ? I learned that it does that by removing more solutes but why does it do so? Thank you
Thank you for the kind words. This is because the counter-current mechanism is imperfect. Note that the blood leaving the vasa recta is slightly hyperosmotic compared to the blood entering the vasa recta. Therefore excess solute is continually "washed out" of the medulla. This entails that as flow rate increases, the rate of solute "washed out" of the medulla also increases. Make sense?
The counter current mechanism is imperfect, so invariably a fraction of the solute occupying the medullary ISF is carried away. This is actually a good thing, however, as it prevents the solute concentration in the medullary ISF from reaching a saturation point (where it would begin to precipitate into crystals)
this topic confused me so much in the first place because the vasa recta are described to have a role in "preserving medullary hyperosmolarity" whereas if it was worded as "providing perfusion without DISRUPTING medually osmolarity" it would've been so much easier to understand
Trank you for the video, it helped me a lot! But I have a question because it came up on a exam, one of the Vorrech answers was, that if the renal bloodflow increases the the osmolarity in the medulla will decrase. How does that work?
Hi Bambii! That is correct. The osmolarity of the blood leaving the vasa recta is a little higher than the osmolarity of the blood entering the vasa recta. This means that counter-current exchange minimizes solute washout, but does not eliminate it completely. The total amount of that excess solute carried away by the vasa recta is a function of the rate of blood flow through the vasa recta, where increasing blood flow increases the rate of solute exiting the medulla. This produces a reduction in osmolarity within the medulla. Make sense?
@@PeteMeighan Hey, thanks for the vid. Ive heard that blood entering vasa recta is at 300, and blood leaving it is at 325. So, I wanted to ask, why does the vasa recta carry away excess solutes? Like, in the descending limb, the blood gains salt and loses water. In the ascending limb, the blood loses salt and gains water. Why dont these effects cancel eachother out and why is there a net gain in water and even more so salts. Does it have anything to do with plasma proteins?
The vasa recta capillaries are not the same as the tubular vessels. It is true that the descending loop of Henle is impermeable to water, but blood vessels are permeable to water due to their simple squamous endothelial nature.
+gertrude micallef Pete should've simply written that he's talking about the blood vessel here (vasa recta) not the nephron. Vasa recta reabsorbs the stuff nephron filters.
My god this has got to be the best, and probably the only explanation on UA-cam, which actually explains the counter current system of the Vasa Recta, and not just the Loop of Henle! Thank you so much Pete!!!!!!!!!!!
This is the only source on the entire internet that helped me understand this topic omg you're the best thank you thank you xxx
Divya Gautam is it
Man .. this 5 minute video helped me a lot
So THANK YOU .. and you’re helping thousands of people OVER 7 YEARS ! .. YOU ARE A REAL HERO 🤝
Nope. Blood flows from the AFFERENT arteriole to the GLOMERULUS to the EFFERENT arteriole to the PERITUBULAR CAPILLARY (PTC). The VASA RECTA is a specialized section of the PTC for juxtamedullary nephrons. Therefore, the EFFERENT arteriole immediately precedes the VASA RECTA.
You are amazing. The way you narrate and explain is clear to understand yet retains all the complexity needed for a high level of education. Thank you.
Very eloquent explanation. Perfectly articulated sentences. Bravo!
the best explanation for countercurrent mechanism on the whole of youtube! bravo! :)
I have watched probably 20 youtube videos on countercurrent exchange and this is the ONLY one that allowed me to properly comprehend. Thank you!
I'm glad this one helped. Thank you for the positive comment!
Thank you so much for this! Such a well thought out and comprehensive explanation! Thanks Prof!
I was so confused on this topic, and I completely get it now. Thank you SO much!!
Love it! After many mins trying to remind myself of this concept I learned long ago, I thankfully found a great video.
this was more helpful than my in person professor.
luh u papi
Thankyou so much I finally understand this. Nice to know someone actually knows what they are talking about.
Thank you so much. My head feels a lot more calm now!
Magnificent explanation, professor! Made things crystal clear.. Thank you!
you now had saved a person from drinking acid because of this exactly !! :D
Thank you Sir !!
To me, this video did the job! Thanks a lot:-)
I think some of the comments below fail to appreciate that this video focuses exclusively on the role of the vasa recta.. the glomerulus and the origin of the CCM and all that, you should look for elsewhere guys!
Your videos are really helpful,thank you..
Couldn't understand this concept but now I do! Thank you!!
Clearly and easily understanding explanation Dr.Paul from Tanzania Africa
Thank you for the kind words. I sincerely appreciate it!
@@PeteMeighan welcome to Africa in Tanzania we are appreciate you for your kindly help thanks
your explanation is crystal clear!!!!!!!!
This is the only explanation that actually made me understand about this thing. I've Googled enough to say that this explanation helps a lot!
Thank you so much for the kind words! I'm glad my video was helpful
Best explaination. Thank you!
this explanation is fantastic!
Best explanation in so far!!
fresh video. honored to comment first.
this was helpful, thank you Pete
Vasa recta just means straight (=recta) arteries of the kidney. It is another system next to the loop of henle which primarily allows for perfusion of the kidney - so basically its a source of blood supply to the kidney + helps maintain the countercurrent mechanism. Hope that helps.
This is so helpful for my exam, thank you!
Thanks! very clear explanation! I finally get this!!
Very good video, it helped me a lot!
Can you briefly explain the movement of the water?
Excellently explained
The best explanation ever👏👏👏
beautiful explanation! sir
THANK YOU!!! FINALLY UNDERSTAND THIS
thank you so much!! this was so much more helpful than my lecture lol
Gr8 explanation!
thank you. this was very helpful.
Best explanation 👌
ty so.. so... much fa dis vdo finally i understood it
finally! thank you!
Thank you !!!
So i can conclude that:
1. The medulla need blood supply (vasa recta) to provide oxygen and reabsorb solute (send to circulation)
2. But if all the solute is taken away, it will disrupt the osmotic gradient
3. So in order to prevent this, counter current arrangement is used (to minimize solute taken away from the medullary interstitium)
4. A small portion solute is taken away to circulation (but most are released back into the interstitium at ascending limb)
5. This way, the osmotic gradient is conserved
Green Rocket--all correct, nice summary! It's worth mentioning that point #4 (i.e., some solute carried away) has an important role for regulating salt/water handling in the kidneys. A variety of regulatory systems can impact the rate of renal blood flow, ultimately modulating the amount of solute that is carried away by circulation (with its attendant effect on the osmotic gradient).
@@PeteMeighan thanks to your video also!! Its amazing how a simple and short video can explain this! Keep up the good work
Thanx alot it helps me
Thanks
Thank you so much!! Finally understood😊
Glad it helped!
thank you
@YATIN PATEL.
No because this is the vasa recta which is more distal to the glomerulus. Afferent ---> glomerulus ----> efferent ---> peritubular capillaries or vasa recta --> branch of renal vein
Thank You
Thank you sir
great 👍
YAY .. you saved me
Its correct dude. This is not glomerulus. This is vasa recta ( specialized peritubular capillaries)
Amazing explanation. I am wondering how does the increased blood flow into vasa recta diminish the gradient ? I learned that it does that by removing more solutes but why does it do so? Thank you
Thank you for the kind words. This is because the counter-current mechanism is imperfect. Note that the blood leaving the vasa recta is slightly hyperosmotic compared to the blood entering the vasa recta. Therefore excess solute is continually "washed out" of the medulla. This entails that as flow rate increases, the rate of solute "washed out" of the medulla also increases. Make sense?
Why is counter current mechanism ignored by UA-cam I don't find good explanation
Tx Pete.
Isn't the descending limb is impermeable to solutes?
what happens if blood flow through the vasa recta is too fast?
Lollll, I'm still confused, thanks anyway
Ikr
same
Thankkk youu
Aha ic thankyou :)
Why is the osmolarity in the end of the Ascending limb higher than in the start of the Descending limb? (350 mOsm vs 300 mOsm)
The counter current mechanism is imperfect, so invariably a fraction of the solute occupying the medullary ISF is carried away. This is actually a good thing, however, as it prevents the solute concentration in the medullary ISF from reaching a saturation point (where it would begin to precipitate into crystals)
this topic confused me so much in the first place because the vasa recta are described to have a role in "preserving medullary hyperosmolarity" whereas if it was worded as "providing perfusion without DISRUPTING medually osmolarity" it would've been so much easier to understand
I smiled when I saw this comment. Earlier in my training, I struggled with this exact lack of clarity. Thank you for the comment.
Shouldnt EFFERENT be AFFERENT?
Trank you for the video, it helped me a lot! But I have a question because it came up on a exam, one of the Vorrech answers was, that if the renal bloodflow increases the the osmolarity in the medulla will decrase. How does that work?
Hi Bambii! That is correct. The osmolarity of the blood leaving the vasa recta is a little higher than the osmolarity of the blood entering the vasa recta. This means that counter-current exchange minimizes solute washout, but does not eliminate it completely. The total amount of that excess solute carried away by the vasa recta is a function of the rate of blood flow through the vasa recta, where increasing blood flow increases the rate of solute exiting the medulla. This produces a reduction in osmolarity within the medulla. Make sense?
Pete Meighan Ah yes, I understand it now, thank you!
Sorry for the misspellings in my question, I just saw them, autocorrect is sabotaging me. 😅
Haha. No worries! I'm frequently on the wrong side of autocorrect. I'm glad my explanation helped!
@@PeteMeighan Hey, thanks for the vid. Ive heard that blood entering vasa recta is at 300, and blood leaving it is at 325. So, I wanted to ask, why does the vasa recta carry away excess solutes? Like, in the descending limb, the blood gains salt and loses water. In the ascending limb, the blood loses salt and gains water. Why dont these effects cancel eachother out and why is there a net gain in water and even more so salts. Does it have anything to do with plasma proteins?
Not too bad description.
I mean efferent arteriole is correct
SAVIOR
What does ISF mean?
interstitial fluid (i.e., the fluid outside of cells).
@@PeteMeighan thank you sir
Does vasa recta mean loop of henle?
It has been 6 years but: no
The descending limb of the nephron loop is only permeable water, this is not completely accurate
The vasa recta capillaries are not the same as the tubular vessels. It is true that the descending loop of Henle is impermeable to water, but blood vessels are permeable to water due to their simple squamous endothelial nature.
from glomerulus*
Meh-doo-luh-ree
I think efferent should be labelled as afferent
Hi Gertrude. "Efferent" is correct. Please see my comment below. Kind regards. --PM
right Pete, in addition to this afferent doesnt drain to vein instead into efferent. only arteriols of its' kind.
+gertrude micallef Pete should've simply written that he's talking about the blood vessel here (vasa recta) not the nephron. Vasa recta reabsorbs the stuff nephron filters.
Puriyale
Ùùuuù
It's not efferent, it enters from the afferent and leaves the kidney through the efferent.