Renal Regulation of Acid/Base Balance

Question 1

What is the principle of acid-base balance?

Answer 1

input=output

whatever you put in must go out

Question 2

What are the 5 points of entry for acids and bases?

Answer 2

1. De novo from metabolism
2. Processing of digested foods
3. GI tract from digestion
4. Metabolism of stored fat and glycogen
5. Kidneys

Question 3

What is a buffer?

Answer 3

a buffer is solution that prevents large changes in pH after the addition or loss of protons from external sources

Question 4

What is the dominant buffer int the ECF?

Answer 4

Bicarbonate-HCO3-

Question 5

What is the dominant buffer int the ECF?

Answer 5

Bicarbonate-HCO3-

Co2 + H20—H2Co3

Question 6

What is the dominant buffer of the ICF?

Answer 6

Phosphates
Protein
more fluid in ICF then ECF

Question 7

What is acidosis? When a patient has what are the 2 possible causes to choose betwen? and how do you know which it is?

Answer 7

decrease in pH; Increase [H+]
caused by:
-increase in proton conc.-change in ion gap
-loss in base–no change in ion gap

Question 8

What is alkalosis?

Answer 8

increase in PH; decrease [H+]
Caused by:
-Base gain
-decrease proton concentration

Question 9

What 2 structures within what structure in the kidney handle acids and bases?

Answer 9

1. Proximal Tubule
   -reabsorb an enormous amount of bicarb
2. Distal Tubule
   -secrete H+ or bicarb(always reabsorbed first) to balance net output
   Both are structure throughout/within the nephron

Question 10

How do we move/buffer fluid between ECF and ICF?

Answer 10

K/H exchanger
Acidosis: H+ into cell/K+out of cell
Alkolosis: H+ out cell/K+ in cell

Question 11

What happens when we keep CO2 in the body? (i.e holding breath, low ventilation)

Answer 11

Increase Co2
Increases [H+]
decrease PH

Question 12

What is the mechanism of Na/H+ exchanger bicarb reabsorption in the distal tubule?

Answer 12

Use an Na/H+ anti-porter-apical membrane that pumps H+ out into lumen– H+ combines with HCO3 to form H2CO3—broken down to water and CO2—Bicarbonate is gone

Na/HCO3 symporter on basolateral membrane
Pumps HCO3 and pumps it back out into the blood—New Bicarb

Question 13

What happens when increase ventilation?

Answer 13

Decrease Co2
Decrease [H+]
Increase PH

Question 14

What hormone increases sodium reabsorption through the Na/H exchanger?

Answer 14

Angiotensin II

Question 15

What are the two cells are found in the distal tubule?

Answer 15

1. Principle

2. Intercalated Cells

Question 16

What are two types of intercalated cells?

Answer 16

1. Type 1 -alpha

2. Type 2- active in alkaosis

Question 17

What is the mechanism of Cl-/HCO3- ?

Answer 17

same mechanism except for Cl being symported together with

Question 18

What are the two types of reabsorption transports in the proximal tubule?

Answer 18

1. Na/H exchanger

2. Cl- Transporter

Question 19

What are 2 types transport mechanism for bicarbonate reabsorption in the in the distal tubule?

Answer 19

1. K/ ATPase

2.

Question 20

What is the mechanism of bicarbonate reabsorption of Type A of distal tubule?

Answer 20

H/K ATPase

—-H2CO3 —breaks down into—HCO3 + H=

Question 21

What are the two responses to excess acid in the blood?

Answer 21

1. HPO4—

2. Amonium

Question 22

What is base load?

Answer 22

excrete base,

excrete bicarb intercalated cells

Question 23

What happens in an acid load ?

Answer 23

excess acid

1. get rid of acid
2. replace lost bicarb with new bicarb

Question 24

What is the mechanism of bicarb formation via titratable acids?

Answer 24

K/H+ exchanger

pumps out H+ combine w/HPO4 and excreted in lumen and HCO3 is resborbed back into interstium

Question 25

Where does the generation of titratable acids occur?

Answer 25

Proximal tubule

Question 26

What is the process of ammonium formation?

Answer 26

catabolism of protein—creation of glutamine— glutamine taken up in the distal tubule–glutamine is converted NH4+ +HCO3—NH4+ secreted into lumen; bicarb exits into interstium

Question 27

How do we quantify how much new bicarb has been made by the kidneys?

Answer 27

NAE =TA+NH4-HCO3

Question 28

Where do we secrete bicarb?

Answer 28

distal tubule

Question 29

What are 4 factors that can cause acidosis?

Answer 29

1. Acid gain
2. Decreased respiration
3. keto-acids
4. base loss diarrhea

Question 30

What are 4 factors that can cause acidosis?

Answer 30

1. decreased respiration
2. keto-acids
3. renal failure
4. base loss diarrhea

Question 31

What causes the formation of keto-acids?

Answer 31

alternate fuel soource

Ketone bodies, seen in diabetes

Question 32

What are 4 factors that can cause acidosis?

Answer 32

1. decreased respiration/ventilation
2. keto-acids
3. renal failure
4. base loss diarrhea

Question 33

What is the anion gap equation?

Answer 33

AG=Na-HCO3

Normal between 8-12

Question 34

What is the point of testing the anion gap?

Answer 34

it allows you to determine acid again or base loss in the body.
if you have acid gain A-, it will increase the u

Question 35

What is the point of testing the anion gap?

Answer 35

it allows you to determine acid again or base loss in the body.
if you have acid gain A-, it will increase the unknown anions in the plasma, therby increasing the gap
if it is a base loss anion gap will stay the same

Question 36

Why will anion gap stay the same when there is a base loss?

Answer 36

chloride will replace the lost bicarbonate

Question 37

What causes alkalosis?

Answer 37

1. Lose acid

2. Gain base

Question 38

What are the 4 ways a patient can develop alkalosis?

Answer 38

1. hyperventilation
2. vomitting
3. bicarb overdose
   4.

Question 39

What are the 4 ways a patient can develop alkalosis?

Answer 39

1. hyperventilation
2. vomitting
3. bicarb overdose
4. chronic dieuretic usage