Test2: Wk7: 3 Renal tubular acidification - Puri

Question 1

kidneys filter — mmol bicarb / day

Answer 1

4320mmol

Question 2

— mmol H+ neutralized by bicarb / day

Answer 2

70mmol

Question 3

the kidneys filter — mmol of bicarb and generate — mmol of new bicarb

Answer 3

4230mmol and 70mmol

Question 4

sodium hydrogen exchanger (NHE) transports H+ in the — and —

Answer 4

PT and TAL

Question 5

H+ primary transporter

Answer 5

HATPase

Question 6

Secondary H+ transporter

Answer 6

HK exchanger - only used with K deficit

Question 7

H+ secretory system is located in

Answer 7

alpha intercalated discs in cortical collecting tubule/ duct

Question 8

hyper aldosterone leads tp

Answer 8

metabolic alkylosis

Question 9

aldosterone has 3 effects

Answer 9

1. directly stimulate H-ATPase
2. ⬆ Na-K-ATPase which ⬆ Na gradient to enter cell
3. ⬆ ENaC activity and number which ⬆ luminal negativity secreting more H+

Question 10

Bicarb Secretory system is located

Answer 10

beta intercalated cells in the cortical collecting tubule/ Duct

Question 11

Bicarb Secretory system is only used during

Answer 11

metabolic alkylosis

Question 12

beta intercalated cells secrete — into the lumen in exchange —

Answer 12

bicarb, Cl-

Question 13

the proximal tubule and the TAL secrete H+ to

Answer 13

reclaim all bicarb

Question 14

The — mediates most of HCO3- absorption in the P.T.

Answer 14

The apical membrane Na/H anti-porter

Question 15

The apical membrane Na/H anti-porter are inhibited by

Answer 15

lithium and amiloride.

Question 16

The Na/H anti-porter is exquisitely sensitive to

Answer 16

H+ concentration on the inside (cytoplasmic side) of the vesicle.

Question 17

— is the Na/H anti-porter subtype predominantly responsible

Answer 17

NHE3

Question 18

NHE3 activity stimulated by (2) and inhibited by (2)

Answer 18

AngII and endothelin; inhibited by PTH and PKA.

Question 19

The Second Step: Generation of “new bicarbonate” and EXCRETION of H+ needs

Answer 19

urinary buffers —phosphates and ammonia

Question 20

Step 1

Answer 20

reabsorb all filtered bicarb

Question 21

Whenever an H+ secreted into the tubular lumen combines with a buffer other than HCO3- the net effect is

Answer 21

addition of a new HCO3- to the blood

Question 22

Metabolically-derived NH3 is the second (and more important)

Answer 22

proton acceptor in the tubular fluid

Question 23

NHE in the proximal tubule and H+-ATPase in the distal tubular segments (intercalated cells) allow

Answer 23

H+ movement into the tubular lumen

Question 24

Protonation of NH3 also leads to synthesis of

Answer 24

one new molecule of HCO3-

Question 25

Combined titrable and non titrable (NH4+) acid secretion equals

Answer 25

the amount of new HCO3- synthesized by the kidneys

Question 26

Net acid excretion should be

Answer 26

the same the amount of new bicarb created

Question 27

NAE =

Answer 27

rate of NH4+ excretion + rate of titratable acid (T.A.) excretion minus rate of HCO3-excretion

Question 28

For each NH4+ excreted, ---- new HCO3- is added to renal venous blood

Answer 28

1

Question 29

For each H+ excreted combined with HPO4- - ( = T.A.) --- HCO3- is added to the renal venous blood.

Answer 29

1

Question 30

bicarb is filtered at the

Answer 30

glomerulus

Question 31

bicarb is consumed by --- and generated ---

Answer 31

H+; daily

Question 32

why is H+ secreted

Answer 32

to reabsorb all HCO3-

Question 33

HCO3- reabsorption conserves extracellular

Answer 33

buffer anion

Question 34

HCO3- reabsorption is driven by

Answer 34

active H+ secretion

Question 35

For each H+ secreted, --- HCO3- is reabsorbed

Answer 35

1

Question 36

In proximal tubule & thick ascending limb % of filtered HCO3- is reabsorbed

Answer 36

90%

Question 37

In proximal tubule & thick ascending limb H+ secretion occurs mostly by

Answer 37

antiport with Na+

Question 38

In proximal tubule & thick ascending limb Minimal urine pH is ---

Answer 38

6.4

Question 39

In proximal tubule & thick ascending limb Carbonic anhydrase acts at the --- of --- and in the --- of ---

Answer 39

luminal membrane (proximal tubule) cytoplasm (proximal tubule and thick ascending limb)

Question 40

In collecting duct intercalated cells --- remaining HCO3- is reabsorbed

Answer 40

Almost all

Question 41

In collecting duct intercalated cells Minimal urine pH is ---

Answer 41

4.4

Question 42

In collecting duct intercalated cells H+ secretion occurs by (2)

Answer 42

H+ ATPase & H+, K+ ATPase

Question 43

In collecting duct intercalated cells Carbonic anhydrase acts

Answer 43

only in the cytoplasm

Question 44

---, ---, and --- stimulate H+ secretion | and HCO3- reabsorption

Answer 44

Falling pH, cortisol and endothelin

Question 45

Elevated PCO2 directly stimulates

Answer 45

H+ secretion

Question 46

As acids consume HCO3- and generate H2CO3 and then CO2, this directly activated --- cells to increase --- activity

Answer 46

PT; NHE

Question 47

By Causing Intracellular Acidosis, Hypokalemia Increases

Answer 47

NHE3 Activity

Question 48

Hypokalemia promotes --- in the distal nephron

Answer 48

H/K exchange

Question 49

High Aldosterone Causes

Answer 49

Alkalosis