(08) - Clearance

Question 1

(GFR is measured as clearance)

1. the volume of plasma cleared of what?
2. [X] in plasma = [X] in what?

all X delieverd as filtrate is excreted in what?

what happns to most of water accompanying X?

3. Clearance of “X” only measures GFR if what occurs?

Answer 1

1. X
2. filtrate

urine

reabsorbed

3. if “X” enters only as filtrate and exits only in final urine

Question 2

(How Can We Measure GFR using Clearance measurements?)

1. Rate of delivery of X as filtrate must equal what?

(How would that be so?)

2. substance freely filtered so that [X]plasma = ?

(Substance must remain in filtrate unchanged until the final urine)

3. reabsorption (removal)?
4. secretion (addition)?
5. degradation in tubules?

Answer 2

1. the rate of delivery of X in final urine
2. [X]filtrate

3-5. no

Question 3

(Inulin - The Gold Standard)

1. inulin is a what?
2. freely filtered.. so [filtrate] = ?
3. are saccharides too large to pass either way through paracellular route (tight junctions)?
4. no transport mechanisms on either side of epithelial cells
5. Are there enzymes (amylases) present in tubular lumen to degrade inulin?

Answer 3

1. polysaccharide
2. [plasma]
3. yes
4. no

Question 4

(Creatinine instead of inulin?)

(creatinine clearance)

1. creatinine excreted solely by filtration in what and what?
2. how much secreted in male dogs?

(creatinine generated at constant rate)

3. non-enzymatic degradation of creatine from what?
4. production must equal what?

Answer 4

1. cats and female dogs
2. small (insignificant?) amount
3. muscle cells
4. excretion

Question 5

(Serum Creatinine Concentration)

1. given that creatinine excreted solely by glomerular filtration and that creatinine production is constant (& level), production must = ?
2. What happens to serum creatinine concentration when GFR drops in half?

Answer 5

1. excretion
2. creatinine concentration doubles

Question 6

Question 7

Answer 7

Question 8

Question 9

Answer 9

E