Clinical GFR and Patterns Of Clearance

Question 1

Ideal substances to calculate GFR?

Answer 1

1. Inulin
2. Mannitol
3. Sucrose

Question 2

Clinical substance used to calculate GFR?

Answer 2

1. Creatinine

Question 3

Creatinine filtration/excretion mechanics?

Answer 3

1. Almost all freely filtered by kidney

2. A small portion is secreted

Question 4

Glucose mechanics in the kidney?

Answer 4

1. Glucose is always reabsorbed until it hits TM (⬆️Glucose concentration)

Question 5

Why is creatinine Clearance > than inulin?

Answer 5

Because some creatinine is always secreted.

Inulin is not secreted nor reabsorbed

Question 6

Normal urine osmolality?

Answer 6

1. 300 mOsm/Kg

Question 7

What does an increase H2O Clearance produce in terms of urine and plasma osmolality?

Answer 7

1. ⬇️ Urine osmolality

2. ⬆️ Plasma osmolality

Question 8

What does an decrease in H2O Clearance produce in terms of urine and plasma osmolality?

Answer 8

1. ⬆️Urine osmolality

2. ⬇️Plasma osmolality

Question 9

Similarities between Sodium and Urea in Kidney mechanics ?

Answer 9

1. Both are excreted and some of it is reabsorbed

Question 10

Aldosterone and ANP effects on FeNa? (Fractional extraction of sodium)

Answer 10

1. Aldosterone: ⬇️FeNa+ (⬆️reabsorption)

2. ANP: ⬆️FeNa+ (⬇️reabsorption)

Question 11

Why does an elevated ADH ⬆️ plasma urea?

Answer 11

⬆️ Urea reabsorption