HardBiologyHigh School (9–10)GeneralLife Processes › ExcretionHuman Body › Excretory SystemNumericalapplication
A patient's blood has 140 mg of urea in every 100 mL.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A patient's blood has mg of urea in every mL. Each hour of dialysis removes of the urea that is left. How many full hours are needed to bring the level below mg per mL? What is the level then?
Need a reminder? The key ideaShow
In each nephron, the glomerulus inside Bowman's capsule filters water, glucose, amino acids, salts and urea out of the blood. The tubule takes back glucose, amino acids, salts and much of the water. What is left is urine. An artificial kidney removes wastes by dialysis, but takes nothing back.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. One hour. mg per mL.
Step 2. Two hours. mg per mL, still too high.
Step 3. Three hours. mg per mL, below .
Answer: full hours, after which the level is about mg of urea per mL.
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