Kidney: Clearance

Question 1

the amount of a substance that is filtered out of the blood by the kidneys

Answer 1

Renal clearance

Question 2

Excretion = ______ – Reabsorption + ______

Answer 2

Filtration

Secretion

Question 3

Measurement of Renal Function is:

Answer 3

Renal Mass Balance

Question 4

Renal Mass Balance

Answer 4

Cra = Crv + Cu

renal artery= renal vein + urine/ureter

Question 5

Cra = Crv if _____ ______

Answer 5

completely reabsorbed

Question 6

Cra = Cu if _____ ____

Answer 6

completely secreted

Question 7

For substances that are not synthesized or metabolized by renal tissue, the amount entering the kidney (via the renal _____) equals the amount leaving the kidney (via the renal _____ and the ____)

Answer 7

artery
vein
ureter

Question 8

the amount of substance entering the nephrons by filtration and/or secretion equals the amount leaving by _____ and/or ______

Answer 8

reabsorption

excretion

Question 9

the use of ______ _______ provides the means for indirectly measuring renal blood flow, glomerular filtration rate, and the rates of tubular reabsorption and secretion of various substances.

Answer 9

mass balance

Question 10

flow can be determined by measuring the mass balance of a substance that is not synthesized or metabolized by the kidney.

Answer 10

Renal plasma flow

Question 11

The difficulty of obtaining renal venous plasma samples limits the usefulness of mass balance approach to measuring RPF so we measure excretion of something “______” cleared from blood

Answer 11

completely

Question 12

the tubular secretory system for ________ is so efficient that at low plasma concentrations it removes 90% or more of the ____ from the plasma as it flows through the kidney, the

Answer 12

para-aminohippurate (PAH)

PAH

Question 13

The total plasma volume filtered by the glomeruli per unit time (GFR) can be measured using a substance that is _____ filtered but is not reabsorbed or secreted, so that the amount excreted equals the amount filtered, such as inulin

Answer 13

freely

Question 14

____ is a fructose polysaccharide (molecular weight ~ 5000)
The amount of ____ filtered per unit time by the glomeruli equals the volume of plasma filtered/time (GFR) times the plasma concentration (Pin)

Answer 14

inulin

inulin

Question 15

Since the ______ cells do not add or remove inulin from the filtrate, the amount entering the nephrons equals the amount exiting by excretion

Answer 15

tubular

Question 16

GFR = Cu x Volume of urine / Cra

if substance is _____ only

Answer 16

filtered

Question 17

GFR = Excretion rate of _____ = clearance of inulin

Answer 17

inulin

Question 18

a waste product of amino acid metabolism

Answer 18

Urea

Question 19

Clearance of Urea is to the ___ of the Inulin curve for renal clearance

Answer 19

right

Question 20

Clearance for Urea is to the ____ of Inulin-clearance curve because it is cleared at a slower rate.
This tells us that since the same amounts of inulin and urea were filtered, some urea was ______

Answer 20

right

reabsorbed

Question 21

If the curve of substance ‘X’ was to the left of the Inulin-clearance curve:

What does that tell you about substance ‘X’?

Answer 21

It secreted! Ex. Penicillin

Question 22

at very low urine floe rates, about 40% of filtered urea is _____

Answer 22

excreted

Question 23

as urine flow rises to 2 ml/min, fractional urea excretion _______ rapidly

Answer 23

increases

Question 24

urea is reabsorbed by a _____ process that depends on water reabsorption to establish a chemical gradient across the tubular wall. Thus when water reabsorption is reduced, urea reabsorption ____

Answer 24

passive

falls

Question 25

all filtered glucose is reabsorbed at plasma concentrations below ____mg/dl
the reabsorption mechanism becomes saturated at plasma concentrations above ____mg/dl

Answer 25

250

350

Question 26

the clearance of glucose is 0 when the plasma concentration is below ____mg/dl, because no glucose is excluded.
Above that concentration, glucose concentration ____ and begins to approach the clearance of inulin

Answer 26

250

rises

Question 27

for a substance that is filtered only, the clearance _____

Answer 27

does not change

Question 28

for a substance that is reabsorbed, the clearance tends to _____

Answer 28

rise

Question 29

for a substance that is secreted, the clearance tends to ____

Answer 29

fall

Question 30

The _____ _____ expresses the excretion of a solute as a percentage of the filtered load

Answer 30

Fractional Excretion (FE)