Birds and their loop on henle's

[topdent1]

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Destroyer number 57 says that since birds have long loop on henles, they have concentrated urine. That doesn't make sense to me because going down the loop you lose water. Going up the loop, you lose ions, so as a result, the concentration of the fluid inside the loop is the same.

 

[drzakisadiq]

It may sound confusing, but just know bottom line, that the longer the loop of Henle, the more water the animal conserves. I remember I saw a problem once that asked the samething except they used Camels instead of birds. The answer stated that Camels have a long loop of Henle to conserve water. Thus, animals that conserve water by excreting wastes low in H2O like uric acid or he Camel which conserves water for its day in the desert, will have long loops of Henle.

 

[mddang]

The loop of Henle functions to maintain the concentration gradient. The outer cortex is about isotonic with the rest of the body, and the interstitial fluid inner medulla is highly concentrated.

When the filtrate travels down the collecting ducts after having already gone through the loop of henle, water diffuses into the medulla (if vasopressin or whatever the equivalent in birds is that increases the permeability to water is present) from the collecting duct due to the high osmolarity of the medulla.


I guess the longer the loop of Henle is, the more time and distance along the duct the filtrate has to allow water to diffuse from the collecting ducts to the medulla.

 

[osimsDDS]

The loop of Henle functions to maintain the concentration gradient. The outer cortex is about isotonic with the rest of the body, and the interstitial fluid inner medulla is highly concentrated.

When the filtrate travels down the collecting ducts after having already gone through the loop of henle, water diffuses into the medulla (if vasopressin or whatever the equivalent in birds is that increases the permeability to water is present) from the collecting duct due to the high osmolarity of the medulla.


I guess the longer the loop of Henle is, the more time and distance along the duct the filtrate has to allow water to diffuse from the collecting ducts to the medulla.

That is correct, also the long it is on the ascending part the more ions such as Na+ can diffuse out of the loop and causing a larger gradient for water to be absorbed when the urine travels into the collecting duct...when it then travels through the collecting duct the permeability of water is the same but since there is a waaay higher concentration in the medulla because more ions due to the longer loop more water can be absorbed...so basically it has to do with higher hyperosmolarity gradient on the ascending part of the loop of henle...