Gene Models & Nephron Function III

Question 1

What do the connecting tubules connect

Answer 1

late distal tubule to cortical collecting duct

Question 2

What are the two cell types in the late distal tubule

Answer 2

principal, intercalated

Question 3

What is secreted in the Late distal tubule and collecting duct

Answer 3

K+ and H+

Question 4

What do the principal cells reabsorb

Answer 4

Na+, H2O

Question 5

What do the principal cells secrete

Answer 5

K+, H+

Question 6

What are the two types of intercalated cells

Answer 6

alpha and beta

Question 7

What is secreted/reabsorbed in the intercalated

Answer 7

H+ and HCO3- are secreted and reabsorbed

Question 8

What channels are on the apical side of the principal cells

Answer 8

ENaC, ROMK, Aquaporin 2

Question 9

What channels are on the basolateral side of the principal cells

Answer 9

Kir2.3, AQP3, AQP4, sodium potassium ATPase

Question 10

What is the function of the principal cell

Answer 10

regulation of urine composition

Question 11

What is the function of Kir2.3

Answer 11

maintain negative membrane potential, and low intracellular sodium conc

Question 12

What regulates ENaC in the principal cell

Answer 12

signalling pathways - phosphorylation

Question 13

What does reabsorption of sodium in the principal cell drive

Answer 13

potassium secretion

Question 14

Which channels are not regulated in the principal cell

Answer 14

AQP3, AQP4

Question 15

What does the number of AQP2 channels depend on

Answer 15

fluid in the body

Question 16

What is the rate limiting step for water reabsorption across the collecting duct

Answer 16

AQP2

Question 17

What steps up the driving force for water reabsorpion

Answer 17

high conc of sodium and potassium in interstitial fluid

Question 18

Name some diseases of the principal cells

Answer 18

Diabetes insipidus, Liddle’s syndrome, Pseudohypoaldosteronism

Question 19

What are the symptoms of diabetes insipidus

Answer 19

problems concentrating the urine

Question 20

What channel is affected in diabetes insipidus

Answer 20

AQP2

Question 21

What channel is affected in Liddle’s syndrome

Answer 21

ENaC

Question 22

Describe symptoms of Liddle’s syndrome

Answer 22

hypertension, too much reabsorption of sodium and water

Question 23

What do the symptoms of pseudohypoaldosteronism mimic

Answer 23

low levels of hormone aldosterone

Question 24

What is amiloride

Answer 24

potassium sparing diuretic

Question 25

What does amiloride block

Answer 25

ENaC, sodium and water reabsorption

Question 26

What does amiloride target

Answer 26

principal cells

Question 27

What does amiloride treat

Answer 27

high BP

Question 28

TRUE or FALSE - alpha intercalated cells have a proton pump on the apical membrane

Answer 28

True

Question 29

What is the function of the proton pump in the alpha intercalated cell

Answer 29

hydrolyse ATP - pump hydrogen ions out against conc grad

Question 30

What channels are located on the basolateral membrane of the apical intercalated cell

Answer 30

halogen ion channel - AE1, chloride channel

Question 31

What is the function of the chloride channel in the alpha intercalated cell

Answer 31

recycling of chloride across basolateral membrane

Question 32

What is the function of AE1 in the alpha intercalated cell

Answer 32

moves bicarbonate out - reabsorbed

Question 33

Why is reabsorption of bicarbonate important

Answer 33

regulation of body fluid pH

Question 34

What disease is associated with alpha intercalated cells

Answer 34

distal renal tubular acidosis

Question 35

What causes distal renal tubular acidosis

Answer 35

mutation in AE1 - basolateral membrane

Question 36

What happens to cells when AE1 is mutated

Answer 36

AE1 appears on both membranes - bicarbonate is lost

Question 37

What are the symptoms of distal renal tubular acidosis

Answer 37

metabolic acidosis, low body fluid pH, renal damage, nephrocalcinosis

Question 38

Describe the permeability of the medullary collecting duct

Answer 38

high permeability to water, urea, low sodium permeability

Question 39

When is the medullary collecting duct permeable to water and urea

Answer 39

in the presence of vasopressin

Question 40

What are the symptoms of acute renal failure

Answer 40

fall in glomerular filtration rate, accumulation of urea, creatinine

Question 41

How is acute renal failure treated

Answer 41

dialysis

Question 42

TRUE or FALSE - acute renal failure is irreversible

Answer 42

FALSE

Question 43

What are the symptoms of acute renal failure

Answer 43

hypervolalemia, hyperkalaemia, acidosis, high urea/creatinine

Question 44

What is hypervolaemia

Answer 44

oliguria due to low GFR

Question 45

What does hyperkalaemia cause in acute renal failure

Answer 45

cardiac excitability, risk of cardiac death