Lect 2 - Block 3 - Renal Function and Clearance

Question 1

Renal plasma flow

Answer 1

Volume of blood flow to kidneys without cells

Question 2

Tubular load

Answer 2

GFR x plasma concentration of substance

Question 3

Urinary excretion

Answer 3

mL/min of urine (1mL/min is normal) with concentration of compound

Question 4

Renal resorption

Answer 4

From tubule into peri tubular capillary

Question 5

Renal secretion

Answer 5

From peritubular capillary to renal tubule

Question 6

7 functions of kidneys

Answer 6

1. Remove nitrogenous wastes from protein metab.
2. Regulate volume and composition of ECF
3. Acid-Base balance
4. Blood pressure regulation
5. Removal of drugs and other foreign substances
6. Release erythropoietin to control RBC production
7. Convert precursor into active vitamin D3

Question 7

Plasma creatinine concentration is _________ proportional to GFR.
Increasing plasma creatinine concentration from 1-2% reflects a loss of _______ of the normal GFR.
Normal GFR is _______

Answer 7

Inversely
Half
120

Question 8

Clearance - a flow of plasma from which a substance is completely removed by the kidneys

C=(___x____)/_____

Answer 8

C=(U x V)/P

Question 9

Used to measure GFR

Answer 9

Inulin
MW 5000
Freely filtered, not secreted, not resorted, not metabolized, doesn’t change GFR, not produced
GFR=(U(in) x V)/P(in)

Question 10

PAH (para-aminohippuric acid) reflects the combination of _______ and ________

Answer 10

Amount filtered (GFR) and the amount secreted (tubular secretion)

Question 11

PAH is used to measure _________, when used in the equation for GFR

Answer 11

Renal plasma flow (RPF)
RPF=(Cpah)/0.9
RPF = true renal plasma flow, corrected for the 90%

0.9 because transport proteins are only 90% effective - only about 90% of PAH which enters the kidneys exits by way of urine (effective renal plasma flow)

Question 12

Free water clearance

Answer 12

The amount of water that has been added to or removed from the isotonic solution to result in the urine osmolarity

Positive free water clearance is dilute urine
Negative free water clearance is concentrated urine

Free water clearance estimated from urine:plasma osmolarity ratio (U/P ratio)

Question 13

Urine osmolarity is used to measure __________ in patients

Answer 13

Relative dehydration

Question 14

Normal plasma osmolarity

Answer 14

300mOsm/L +/- 10%

Question 15

Renal delivery is calculated as

Answer 15

(Plasma concentration)(renal plasma flow)=renal delivery

Question 16

Tubular load is calculated by

Answer 16

(Plasma concentration)(GFR)=tubular load

Question 17

Urinary excretion is calculated as

Answer 17

(concentration of compound in urine)(urine flow)=urinary excretion
1mL/min is normal urine flow

Question 18

Glucose is (filtered, excreted, reabsorbed, secreted)

Answer 18

Filtered, reabsorbed fully

Question 19

Albumin is (filtered, excreted, reabsorbed, secreted)

Answer 19

Not filtered, too big

Question 20

Na+ is (filtered, excreted, reabsorbed, secreted)

Answer 20

Filtered, reabsorbed, excreted

Question 21

Creatinine is (filtered, excreted, reabsorbed, secreted)

Answer 21

Filtered, excreted

Question 22

Penicillin is (filtered, excreted, reabsorbed, secreted)

Answer 22

Filtered, secreted, excreted

Question 23

The majority of renal oxygen consumption is used for ________ reabsorption

Answer 23

Sodium

Question 24

Renal blood flow

Answer 24

Volume of blood flow from CO to kidneys, 20%