Phys: Test 3. Lecture 20 Acid And Base Balance

Front 1

1. What is the most important buffer system?

Back 1

a. CO2 bicarb

Front 2

2. What is maintaining H balance really about?

Back 2

a. Maintaining HCO3 balance

Front 3

3. What do kidneys do to non-volatile acids?

Back 3

a. Neutralize them

Front 4

4. Kidneys have 2 roles with bicarb, what are they?

Back 4

a. Generate new bicarb
b. Reabsorb bicarb

Front 5

5. What is the sum of GI secretions (acidic/basic)?

Back 5

a. Normally acid base neutral (secreting both)
b. Maybe a slight net bicarb to lumen

Front 6

How do the lungs excrete acid?

Back 6

excrete potential acid in the form of CO2

Front 7

What are 3 sources of fixed acids and bases?

Back 7

Metabolism of dietary protein
metabolism of dietary weak acids (citrus fruit, other vegetables-->will make bases)
anerobic metabolism of carbohydrate and fat

Front 8

What can renal secretion of H and Bicarb be called synonomous to?

Back 8

The parietal cell

Front 9

how does H+ get secreted into the lumen? 2

Back 9

1the good ole Na/H+ antiporter!!
2. H+ ATPase

Front 10

After pumping H+ into the lumen, what happens?

Back 10

it will combine with HCO3 in the lumen, forming H2O and CO2 via the carbonic anhydrase rxn

Front 11

after forming H2O and CO2 via the carbonic anhydrase rxn, what will happen?

Back 11

The CO2 and H2O get taken back up and lead to the formation of HCO3

thus HCO3 is recycled

Front 12

On the basolateral membrane, the typical mechanism is the remove HCO3 with Na, how is it different in the TAL?

Back 12

i. Bicarb out for Cl- instead of co-transport with Na

Front 13

Where is the most filtered bicarb recovered?

Back 13

Proximal tubule

Front 14

What does recovery of HCO3 require?

Back 14

tubular secretion of H ions

Front 15

Besides forming CO2 and Water and the reuptake of Bicarb, what result can H+ secretion have?

Back 15

it can lead to excretion of the the acid PLUS the generation of a NEW HCO3

Front 16

When you excrete H with a buffer other than HCO3, what happens?

Back 16

you will generate a new HCO3

Front 17

What type of cell is responsible for secreting H+ into the lumen?

Back 17

Type A intercalated Cell

Front 18

What cell is responsible for putting HCO3 into the lumen?

Back 18

Type B intercalated cell

Front 19

Net urinary acid excretion=

Back 19

excreted H bound to phosphate/creatine/uric acid + Excreted H bound to NH3 - Excretion of filtered HCO3

Front 20

When H+ is secreted, besides reacting with Bicarb to make H2O and CO2 what can it bind with? what does this lead to?

Back 20

it can combine with filtered phosphate, this causes the formation of new HCO3

Front 21

discuss how glutamine can lead to H+ secretion and what additionally will be formed.

Back 21

Glutamine enters, gets broken into NH4 and HCO3

NH4 gets removed via antiport with Na

NH4 is secreted (thus H+ is removed)

HCO3 is absorbed-->this is a new HCO3

Front 22

BIG IDEA: What are the 3 fates of H secretion?

Back 22

1. Titrate with filtered HCO3 in order to recover the HCO3
2. Titrate with phosphate with H excreted and new HCO3 formed
3. Titrate with NH3 with H excreted in the form of NH4 and create a new HCO3

Front 23

15. 2 big signals for regulation of acid base?

Back 23

a. PaCO2 and arterial pH

Front 24

16. Why is PaCO2 a regulation for acid/base balance?

Back 24

a. Because of its effects on renal intracellular pH

Front 25

Why is arterial pH a regulation for acid/base balance?

Back 25

a. Extracellular pH acts directly on tubular cells

Front 26

in addition to PaCO2 and pH what is an another mechanism for acid/base balance?

Back 26

a. Enhanced Na reabsorption can play a role
b. You will be dumping a lot of hydrogen

Front 27

What type of cells secrete HCO3?

Back 27

Type B intercalacted cells

Front 28

please describe the if there is an increase or decrease in the following for RESPIRATORY ACIDOSIS:
pH
H+
HCO3
PCO2

Back 28

pH: decrease
H: increase
HCO3: increase
PCO2: large increase

Front 29

what is the compensatory response for respiratory acidosis?

Back 29

kidneys increase H+ secretion

Front 30

please describe the if there is an increase or decrease in the following for RESPIRATORY ALKALOSIS:
pH
H+
HCO3
PCO2

Back 30

pH: increase
H+: decrease
HCO3: decrease
PCO2: decrease

Front 31

please describe the if there is an increase or decrease in the following for Metabolic acidosis:
pH
H+
HCO3
PCO2

Back 31

pH: decrease
H+: increase
HCO3: decrease
PCO2: decrease

Front 32

major compensatory response to metabolic acidosis?

Back 32

alveolar hyperventalation; increase H+ excretion

Front 33

major compensatory response to respiratory alkalosis

Back 33

kidneys increase HCO3 excretion

Front 34

please describe the if there is an increase or decrease in the following for Metabolic alkalosis:
pH
H+
HCO3
PCO2

Back 34

pH: increase
H+: decrease
HCO3: increase
PCO2:increase

Front 35

compensatory response for metabolic alkalosis?

Back 35

alveolar hypoventalation, kidneys increase HCO3 excretion

Front 36

5. What does enhanced sodium reabsorption lead to in the kidney?

Back 36

a. Enhanced H+ excretion

Front 37

6. What will changes in plasma K concentration do?

Back 37

a. Change the acid base balance

Front 38

when there is low plasma K+ what happens to K+ and H+

Back 38

K+ is secreted into plasma and H+ moves in to the cell

Front 39

what is the relationship of movement btw K+ and H+

Back 39

they move in opposite directions

Front 40

When there is high K plasma what happens to K+ and H+

Back 40

K+ goes into the cell and H+ goes into the plasma

Front 41

If you have hypokalemia, what type of acid/base dysfunction will you have?

Back 41

Alkalosis

Front 42

if you have hyperkalemia what type of acid/base dysfunction will you have?

Back 42

acidosis

Front 43

7. If you decrease Plasma K what happens?

Back 43

a. K+ will get drawn out of cells
b. H+ will get drawn into cells
c. This will lead to METABOLIC ALKALOSIS

Front 44

What response do kidneys have hypokalemia?

Back 44

Increase renal H+ secretion and reabsorption of HCO3 and generation of HCO3

aka, it makes the effect worse

Front 45

what response do the kidneys have to hyperkalemia?

Back 45

decrease renal secretion and decreased reabsorption of HCO3 and generation of new HCO3

aka make the acidosis worse

Front 46

9. What will hyperaldosteronism lead to?

Back 46

a. HYPOKALEMIA (which leads to alkalosis)
b. AND the aldosterone all by itself directly stimulates H secretion which leads to further alkalosis

Front 47

10. Hypoadosteronism causes??

Back 47

leads to increase in plasma K (hyperkalemia) leading to acidosis

Front 48

What effect does aldosterone have on the type A intercalated cells?

Back 48

stimulates H-ATPase

Front 49

what does aldosterone do Na reabsorption?

Back 49

increases it at the collecting duct, and promotes more H+ secretion as a result (lumen becomes negative)

Front 50

What does aldosterone do to K?

Back 50

leads to K secretion, thus hypokalemaia (and thus H+ secretion and alkalosis)

Front 51

12. What will Changes in Volume do with respect to K?

Back 51

a. Depletion of water
i. Start using aldosterone to keep water in
1. Will end up leading to metabolic alkalosis because of K+ secretion