Acid-base 1 Flashcards
normal blood pH
7.4
what is formula for pH
-log[H]
what is typical buffer
weak acid and its conjugate base
3 keys to a good buffer
- need high [c] available
- need to be able to restore buffer when used
- pK ph buffer should be near pH of body fluid
what is pK
pH at which [HA] = [A-]
bronstead lowry def of acid base
acid is H donor and base is H acceptor
what is blood buffer system
H+ + HCO3- <> H2CO3 <> H2O + CO2
normal blood levels
H+ = 40 HCO3 = 24 CO2 = 40
why does CO2 not increase when HCO3 binds with H to buffer
blow off excess respiratorily
where is more HCO3 coming from
kidneys
where does most H+ come from
diet (esp protein breakdown)
2 renal responses to acidosis
- reabsorb
2. regenerate - via NH4+ production and secretion
where is HCO3- reabsorbed
PCT
how is HCO3- reabsorbed
- luminar NHE3 exchanger pulls NA in off NaHCO3
- Na crossing drives H+ into tubule
- H+ reacts with HCO3- which makes CO2
- CO2 goes into blood
- leftover HCO3- goes into blood
4 aspects that determine HCO3- reabsorb
- filtered HCO3 load - less reabsorb
- luminal [H] - more reab
- ICF [H] - more
- avidity for Na reabsorb - more
what is kidney response to more acid from diet
- sensors activate to low pH
- kidney excretes more acid in form of NH4+
- for each NH4+ excreted, 1 bicarb is made
what is ammonium synthesized from
ammonium
3 steps in ammoniagensis
- proximal NH4+ prod from glutamine
- NH4 into lumen and made to NH3 + H
- secreted H from collection duct make NH4 and excreted
