1. describe the composition of urinary casts, and explain how they can get into the urine.
2. proteinuria and the presence of numerous casts in the urine sediment are often accompanied by edema. What is the relationship between these symptoms?
3. suppose substance "A" is reabsorbed about 30%, whereas substance "B" is secreted about 30%. Explain how their renal plasma clearance values relate to each other and to the glomerular filtration rate (GFR).