acid and base

Question 1

what are the volatile and non-volatile acids produced with respect to blood an renal systems

Answer 1

1. volatile acid
   
   1. CO2
2. nonvolatile acid
   
   1. phsophoric, lactic and sulfuric
   2. ketoacids produced on pathological conditions

Question 2

what are the three mechanisms (general) for handeling the pH and what is the normal pH?

Answer 2

1. mechanisms
   
   1. intracellular and extracellular buffering
   2. respiratory compensation alteration in breathing depth and rate
   3. renal compensation
2. pH
   
   1. acidemiea<7.37-normal-7.42

Question 3

What is the description of a buffer?

Answer 3

Buffer

1. weak acid conjugated to a weak base
2. resist pH change
3. main in the ECF = HCO3-
   
   1. buffers volatile and nonvolatile acids
4. main buffer in ICF = proteins, inorganic phosphates and organic phosphate

Question 4

what are the main buffering sources of ICF and ECF?

Answer 4

Buffer

1. weak acid conjugated to a weak base
2. resist pH change
3. main in the ECF = HCO3-
   
   1. buffers volatile and nonvolatile acids
4. main buffer in ICF = proteins, inorganic phosphates and organic phosphate

Question 5

explain what it means to be below the pK.

Answer 5

1. titratable acids refers to acids that can be titrated with NaOH to a pH of 7.4 (that of normal plasma)
   
   1. pH=pK, [conjugatebase]=[conjugate acid]
      
      1. this is where buffering capacity is the greatest
   2. below pKa
      
      1. more of the ocmpound is in acid form
      2. adding more OH- convertrs tha acid to its conjugate base and combint the H with OH- = increasing the pH.
      3. climbing above pKa value depeletes the acid and accumulates the conjugate base

Question 6

Where if the buffering capacity the greatest for a buffer?

Answer 6

1. titratable acids refers to acids that can be titrated with NaOH to a pH of 7.4 (that of normal plasma)
   
   1. pH=pK, [conjugatebase]=[conjugate acid]
      
      1. this is where buffering capacity is the greatest
   2. below pKa
      
      1. more of the ocmpound is in acid form
      2. adding more OH- convertrs tha acid to its conjugate base and combint the H with OH- = increasing the pH.
      3. climbing above pKa value depeletes the acid and accumulates the conjugate base
         3.

Question 7

Kidneys rol in acid-base homeostasis (2-general description)

Answer 7

• roles
  
  • reabsorb filtered HCO3
  • compensate forbuffer lost by conjugation to nonvolatile acids in plasma

Question 8

what is a better term to describe the absorption of bicarb? why?

Answer 8

1. becarbonate reabsorption aka reclamation
   
   1. rather tha absorption, the filtered moiety is destroyed and a new one is produced in its stead.
2. reclamation occurs in PT or excreted
   
   1. when in doubt, choose PT

Question 9

Where does reclamation of bicarb occur?

Answer 9

1. becarbonate reabsorption aka reclamation
   
   1. rather tha absorption, the filtered moiety is destroyed and a new one is produced in its stead.
2. reclamation occurs in PT or excreted
   
   1. when in doubt, choose PT

Question 10

decribe the location and process of bicarb reclamation

Answer 10

1. apical
   
   1. tubular brush border = carbonic anhydrase cleaves HCO3- -> H2O + CO2
      
      1. OH- combines with excreted H+ and generates water
      2. HCO3- combines with H+ and generates H2CO3-> reacts with CA-> H2O +CO2= inert and moves through membrane
2. intracellular
   
   1. carbonic anhydrase recombines CO2 and H2O to generate HCO3 and H
   2. H is pumped into the lumen, Na/H exchanger (antiporter)
   3. HCO3 is pumped into the interstitium- mainly occurs in TAL, a little in PT
      
      1. Na/HCO3 symptorter
      2. Cl/HCO3 antiporter

Question 11

what enzymes/transporters are active on the apical and basolateral side of the PT cells?

Answer 11

1. apical
   
   1. tubular brush border = carbonic anhydrase cleaves HCO3- -> H2O + CO2
      
      1. OH- combines with excreted H+ and generates water
      2. HCO3- combines with H+ and generates H2CO3-> reacts with CA-> H2O +CO2= inert and moves through membrane
2. intracellular
   
   1. carbonic anhydrase recombines CO2 and H2O to generate HCO3 and H
   2. H is pumped into the lumen, Na/H exchanger (antiporter)
   3. HCO3 is pumped into the interstitium- mainly occurs in TAL, a little in PT
      
      1. Na/HCO3 symptorter
      2. Cl/HCO3 antiporter

Question 12

what are the three locations for H excretion?

Answer 12

1. PT- little
   
   1. H/NA antiporter
2. TAL- many
   
   1. Na/H antiporter
3. MCD
   
   1. K/H antiporter

Question 13

What is the cost to neutralize an acid? how is this managed?

Answer 13

1. acids are neutralized in the blood at a cost of base
   
   1. new base synthesized to replace that loss
   2. lowest urine pH=4.4
2. protons bound to buffers, most commonly to form dihydrogen phosphate

Question 14

Describe how dihydrogen phosphate is formed in the kidneys. Why does it make a really good buffer?

Answer 14

generation of New HCO3- by forming a titratable acid

• HPO2(conjugate base)+H-> H2PO4-(conjugate acid)

1. properties
   
   1. pK=6.8
      
      1. this means it holds onto the H as the pH drops
   2. conjugate base has a high rate of excretion, freely filtered
   3. conjugate acid is not absorbed
2. HCO3 is secreted on the basolateral side (NOT THE APICAL)

Question 15

during dihydrogen phosphate generatation, where is the HCO3 secreted and the H secreted?

Answer 15

generation of New HCO3- by forming a titratable acid

• HPO2(conjugate base)+H-> H2PO4-(conjugate acid)

1. properties
   
   1. pK=6.8
      
      1. this means it holds onto the H as the pH drops
   2. conjugate base has a high rate of excretion, freely filtered
   3. conjugate acid is not absorbed
2. HCO3 is secreted on the basolateral side (NOT THE APICAL)
   
   1. generated from free OH- and CO2

Question 16

why is dihydrogen phosphrus titratable and ammonium not?

Answer 16

1. not filtered
   
   1. produced along with OH- in the epithelial cell by metabolism of Glutamine
2. during the glut metabolism
   
   1. HCO3- secreted into the basolateral side
      
      1. OH- and CO2 combine via carbonic anhydrase
   2. NH4+
      
      1. intracellularly seperates = ammonia + H+
         
         1. ammonia is lipid soluble and diffuses across the membrane
      2. recombines in the lumen
      3. pK >9
         
         1. conjugate acid is very stable and does not dissociate urine
         2. is not titratable, becuase pK is above 7

Question 17

Formation of a new HCO3- from an nontitrable acid. Describe the mechanism.

Answer 17

1. not filtered
   
   1. produced along with OH- in the epithelial cell by metabolism of Glutamine
2. during the glut metabolism
   
   1. HCO3- secreted into the basolateral side
      
      1. OH- and CO2 combine via carbonic anhydrase
   2. NH4+
      
      1. intracellularly seperates = ammonia + H+
         
         1. ammonia is lipid soluble and diffuses across the membrane
      2. recombines in the lumen
      3. pK >9
         
         1. conjugate acid is very stable and does not dissociate urine
         2. is not titratable, becuase pK is above 7

Question 18

Describe the titrable acid and non titrable acid

1. where-formed/secreted/reabsorped(only one)

Answer 18

1. titrable acid synthesis-reclaimation (H2PO4)
   
   1. PT-formed
   2. DCT -formed
   3. IMCD-formed
2. non titratable acid synthesis
   
   1. PT-formed/secreted
   2. tDLH- secreted
   3. TAL--REABSORPTION
   4. OMCD-secreted

Question 19

Formed in the PT, reabosored in the TAL and secreted in the PT, tDLH, and OMCD

Answer 19

1. titrable acid synthesis-reclaimation (H2PO4)
   
   1. PT-formed
   2. DCT -formed
   3. IMCD-formed
2. non titratable acid synthesis
   
   1. PT-formed/secreted
   2. tDLH- secreted
   3. TAL--REABSORPTION
   4. OMCD-secreted