Role of the Kidneys in Acid/Base Balance Flashcards
What is the molarity of [H+] at 7.40 pH?
0.00004 mmol/L
What is the difference between acidosis and acidemia?
Acidemia is the state of having more protons in the blood, while acidosis is the process of getting more acid in the blood.
How much metabolic acid is produced per day?
1 mmol/kg/day
__________ acids must be eliminated by the kidneys.
Nonvolatile
What two molecules often get metabolized to acidic compounds?
Nucleic acids (to phosphaturic acid) and sulfur-containing proteins
How much nonvolatile acid does the average Westerner consume per day?
60 - 70 mmol
List three general pH functions of the kidney.
Eliminate acid anions (sulfuric acid and phosphuric acid) Reabsorb bicarb (~85% in the PCT) Synthesize new bicarb (60 - 70 mmol daily; mainly in the intercalated cells of the DCT)
Essentially no bicarb synthesis can take place until _____________.
bicarb reabsorption is complete
How much HCO3 do we need to synthesize daily?
60 - 70 mmol
Impaired proximal-tubule resorption of bicarb will result in ____________.
proximal renal tubule acidosis
For every proton that is excreted, a new ________ is synthesized.
bicarb (this occurs because CO2 diffuses into the intercalated cells; carbonic anhydrase converts it to carbonic acid; a proton is excreted; and the remaining bicarb is reabsorbed)
What prevents the urinary pH from being so low?
Titratable acids (creatinine, phosphate, and urate) and ammonia trapping keep the pH from being lower than 4.5
NH3 diffuses easily through the _________.
apical membrane of the renal rubule
NH3 binds to ______ and becomes trapped as ______.
H+; NH4+
Ammonia is generated in the ___________ via ___________.
proximal tubule cells; glutaminase