Renal Function 1

Question 1

What are functions of the kidney?

Answer 1

• waste secretion
• maintaining EC volume and composition
• hormone synthesis

Question 2

What is normal GFR?

Answer 2

120ml/min = 7.2L/h

Question 3

What is clearance=

Answer 3

The volume of plasma that can be completely cleared of a marker substance per unit time

Question 4

What are the three criteria that need to be fulfilled for a marker to be used for GFR?

Answer 4

1. Marker NOT bound to serum protein
2. Marker freely filtered by glomerulus
3. Marker not secreted/reabsrbed by tubular cells

Question 5

What is the formula to calculate clearance?

Answer 5

C = (UxV)/P

U = urinary concentration 
V = volume 
P = plasma concentratino

Question 6

What is inulin

Answer 6

A fructose plumes that is technically the perfect marker for GFR

Question 7

Why is inulin not used in practice?

Answer 7

Because the measurement of inulin concentration is difficult, and requires steady state infusion

Therefore it is only used as a research tool

Question 8

What are three clinically viable injectable measures of GFR?

Answer 8

Cr-EDTA
Tc-DTPA
Iohexol

Question 9

What are the two common good endogenous markers of GFR?

Answer 9

Creatinine

Blood urea

Question 10

What does blood urea depend on?

Answer 10

Nutritional state
Hepatic function
GI bleed

Question 11

What are factors that affect serum creatinine in measuring GFR?

Answer 11

Muscularity
Age
Sex (M>F)
ethnicity

Question 12

What is a better endogenous marker than creatinine, that is rarely used?

Answer 12

Cystatin C

Question 13

What are the possible conclusions to be drawn from a urine dipstick ++ for blood?

Answer 13

haermaturiai 
myoglobinuria (from rhabdomyolysis)