Tubular reabsorption and secretion

Question 1

What are the different mechanisms of transport across a cell membrane?

Answer 1

Diffusion
Uniport
Symport/cotransport
Antiport
Ion channel
Active transport

Question 2

What are common characteristics of protein mediated transport?

Answer 2

Rate of transport
Saturation kinetics
Chemical specificity

Question 3

What is the plasma threshold of glucose where the excretion from the kidneys begins?

Answer 3

200 mg/dL

Question 4

Where is the Na/H antiporter located in the kidneys?

Answer 4

Proximal tubule

Question 5

Where is H+ secreted in the kidney?

Answer 5

Proximal tubule
Thick ascending limb
Alpha-intercalated cells in collecting tubule

Question 6

Where is bicarbonate synthesized in the kidney?

Answer 6

Proximal tubule
Alpha intercalated cells in collecting tubule

Question 7

What is the affect of angiotensin II in the proximal tubule?

Answer 7

Stimulates Na/H countertransport

Question 8

What is the site of action of osmotic diuretics?

Answer 8

Proximal tubule - Na/H countertransport

Question 9

What are the osmotic diuretics?

Answer 9

Urea
Glucose
Mannitol

Question 10

What is the site of generation of the medullary osmotic gradient?

Answer 10

Thick ascending loop of Henle

Question 11

What is the site of action of loop diuretics?

Answer 11

NKCC2 transporter in the loop of Henle

Question 12

What tubules are impermeable to water?

Answer 12

Thick ascending loop of Henle
Early distal tubule

Question 13

When does tubular fluid become hypotonic?

Answer 13

Early distal tubule

Question 14

What is the site of action of thiazide-like diuretics?

Answer 14

Early distal tubule - blocks Na/Cl cotransporter

Question 15

What does membrane permeability to water in the principal cells depend on ?

Answer 15

Concentration of ADH

Question 16

What stimulates Na/K antiport in the principal cells?

Answer 16

Aldosterone

Question 17

Where are renal principal cells located?

Answer 17

Late distal tubules and cortical collecting tubules

Question 18

What is the site of action for K sparing diuretics?

Answer 18

Principal cells

Question 19

What is the general movement of sodium through the kidney?

Answer 19

Freely filtered
99.5% reabsorbed
0.5% excreted

Question 20

What does potassium excretion depend on?

Answer 20

Rate of potassium excretion by principal cells

Question 21

About how much of filtered calcium is normally excreted?

Answer 21

Less than 1%

Question 22

About how much filtered phosphate is normally excreted?

Answer 22

About 15%

Question 23

Where is urea reabsorbed in the kidney?

Answer 23

PCT
Collecting duct

Question 24

Where is urea secreted in the kidney?

Answer 24

Thin descending limb

Question 25

What is the defect in Fanconi syndrome?

Answer 25

Impaired reabsorption in proximal tubule

Question 26

What are the effects of Fanconi syndrome?

Answer 26

Metabolic acidosis Hypophosphatemia

Question 27

What is the defect in Bartter syndrome?

Answer 27

NKCC2 cotransporter

Question 28

What are the effects of Bartter syndrome?

Answer 28

Metabolic alkalosis Hypokalemia Hypocalcemia

Question 29

What is the defect in Gitelman syndrome?

Answer 29

Na/Cl transporter in DCT

Question 30

What are the effects of Gitelman syndrome?

Answer 30

Metabolic acidosis Hypokalemia Hypercalcemia

Question 31

What is the defect in Liddle syndrome?

Answer 31

Overactive ENaC in collecting ducts

Question 32

What are the effects of Liddle syndrome?

Answer 32

Metabolic alkalosis Hypokalemia Hypertension Hypoaldosteronism

Question 33

What are lost when using osmotic diuretics?

Answer 33

Unabsorbed sugars, sodium, water

Question 34

What is the effect of carbonic anhydrase inhibitor in the kidney?

Answer 34

Decreased reabsorption of HCO3- Decreased Na/H exchange

Question 35

What is lost when using loop diuretics?

Answer 35

Calcium Potassium Water

Question 36

What is lost when using thiazide-like diuretics?

Answer 36

Potassium

Question 37

What group of diuretics are calcium sparing?

Answer 37

Thiazide-like diuretics

Question 38

What is the primary action of diuretics?

Answer 38

Decrease plasma osmolality

Question 39

What is the secondary action of diuretics?

Answer 39

Increase water excretion