Renal Excretory Function

Question 1

3 parts of the glomerular filtration barrier

Answer 1

Capillary endothelium
Basement membrane
Podocyte foot processes

Question 2

What protein is lost into urine in nephrotic syndrome

Answer 2

Albumin

Question 3

Where is the plasma concentrated to an ultra filtrate

Answer 3

Bowman’s capsule

Question 4

First step of urine formation

Answer 4

Production of plasma ultrafiltrate

Question 5

What determines what substances enter the ultrafiltrate

Answer 5

Net filtration pressure
Podocyte slit pores
Molecule size
Molecule charge

Question 6

What molecules moves freely at the glomerulus

Answer 6

Water
Electrolytes
Urea
Amino acids

Question 7

GFR

Answer 7

Total amount of fluid filtered through the glomerulus

Question 8

What happens to the majority of fluid filtered in the glomerulus

Answer 8

Reabsorbed

Question 9

Why is creatinine used to measure GFR

Answer 9

Freely filtered by glomerulus
Not reabsorbed
Measurable
Produced by body
Already at steady state conc in blood

Question 10

Does creatinine clearance over or under estimate GFR by 10-20%

Answer 10

Overestimates

Question 11

Why does creatinine clearance overestimate GFR by 10-20%

Answer 11

Peritubular capillaries secrete creatinine

Question 12

Creatine clearance calculation

Answer 12

(Urine conc x urine vol) / plasma conc

Question 13

How can GFR be measured

Answer 13

Creatinine clearance
Nuclear medicine scan

Question 14

How can GFR be estimated

Answer 14

MDRD equation - CAGE
Cockcroft gault equation

Question 15

What variables are needed to out into the MDRD equation for estimating GFR

Answer 15

CAGE
creatinine
Age
Gender
Ethnicity

Question 16

What can make GFR from creatinine clearance unreliable

Answer 16

Raised serum creatinine in muscular individuals
Low serum creatinine in malnourished individuals
Raised serum creatinine in individuals on drugs that inhibit Tubular creatinine secretion

Question 17

Does raised serum creatinine cause an over or underestimattion of GFR

Answer 17

Underestimate

Question 18

Is the brush border on the apical or baso lateral side of tubule cells

Answer 18

Apical

Question 19

What limits water and solute movement between tubular cells

Answer 19

Tight junctions

Question 20

How does urea move from the tubular lumen to interstitium in the proximal tubule

Answer 20

Passive diffusion

Question 21

How do sodium phosphate glucose and amino acids move from the tubular lumen into tubular cells in the proximal tubule

Answer 21

Secondary active transport

Question 22

How many Na ions are transported from the tubular cell to the interstitium for very 2 K ions transported from the interstitium to the tubular cell in the proximal convoluted tubule

Answer 22

3

Question 23

Are sodium and potassium transported by primary or secondary active transport in the proximal convoluted tubule

Answer 23

Primary

Question 24

What do defects in the apical Na/cystine cotransporter In the proximal tubule cause

Answer 24

Cystinuria

Question 25

What do defects in the Na/glucose cotransporter in the proximal tubule cause

Answer 25

Renal glycosuria

Question 26

What do defects in the basolateral Na/HCO3 cotransporter in the proximal tubule cause

Answer 26

Proximal RTA

Question 27

What do defects in the apical Na/K/2Cl cotransporter in the thick ascending loop of henle cause

Answer 27

Bartter type 1

Question 28

What do defects in the apical Na-Cl cotransporter in the distal tubule cause

Answer 28

Gitelman’s

Question 29

What are the 2 parts of the proximal tubule

Answer 29

Proximal convoluted tubule - 1st 2/3 Proximal straight tubule - final 3rd

Question 30

Where does 80% of solute reabsorbance occur

Answer 30

Proximal tubule

Question 31

What is pumped out of the descending loop of henle

Answer 31

Water

Question 32

What substances leave the ascending loop of henle

Answer 32

Sodium Potassium Chloride Calcium Magnesium

Question 33

How is high solute concentration maintained deep in the medulla

Answer 33

Vasa react carry salt from top of medulla to deep medulla

Question 34

What is the thick ascending limb impermeable to

Answer 34

Water

Question 35

What ion is transported by both secondary active and paracellular transport in the ascending loop of henle

Answer 35

Sodium

Question 36

Function of the distal nephron

Answer 36

Potassium excretion Na delivery to collecting duct regulated Urine acidification

Question 37

What determines urine conc in the collecting tubule

Answer 37

ADH

Question 38

Renal threshold

Answer 38

Concentration of a substance dissolved in the blood above which the kidneys begin to remove it into the urine

Question 39

What happens when the renal threshold of a substance is exceeded

Answer 39

Some of the substance remains in urine

Question 40

What is the renal threshold for glucose

Answer 40

10mmol/L

Question 41

Osmotic diuresis

Answer 41

Excess solute in the tubular fluid attracts water and increases urine volume