The Bowman's capsule, all or nothing function?

[chaser0]

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Im quite bothered by this new item i learned from EK and was lookin for another voice.

EK notes that if
1.) Solute X is never resorbed or secreted in the nephron, its "clearance" (amount in urine) is equal to its "filtration rate" (amount entering the nephron from the blood).

2.) If 1 is true, then this means that the filtered concentration of solute X is equal to the plasma concentration of solute X.

What?
If urine [solute X]=filtered [solute X]
Then always filtered [solute X]= plasma [solute X]

Could someone explain this to me?
I always asumed that if a solute is filtered, depending on its size, a certain percerage of it would be filtered. Not ALL of it...

 

[MedPR]

Im quite bothered by this new item i learned from EK and was lookin for another voice.

EK notes that if
1.) Solute X is never resorbed or secreted in the nephron, its "clearance" (amount in urine) is equal to its "filtration rate" (amount entering the nephron from the blood).

2.) If 1 is true, then this means that the filtered concentration of solute X is equal to the plasma concentration of solute X.

What?
If urine [solute X]=filtered [solute X]
Then always filtered [solute X]= plasma [solute X]

Could someone explain this to me?
I always asumed that if a solute is filtered, depending on its size, a certain percerage of it would be filtered. Not ALL of it...

Think of it this way. Connect a water hose to a faucet and kink the water hose at a point 3 feet away from the faucet. Turn on the faucet and let the hose fill will water. Turn off the faucet and unkink the hose. How much water comes out? Exactly as much water came in from the faucet. This is what happens when nothing is secreted into or reabsorbed from the renal tubule.