Acid Base Flashcards
the mechanisms for ___________ and __________ compensation occur rapidly, within minutes or hours
buffering; respiratory compensation
the mechanisms for ________ compensation are slower, requiring hours to days
renal
what are two forms of acid production?
volatile acid- CO2
non-volatile (or fixed) acid
____ is the end product of aerobic metabolism in the cells. Is this an acid?
CO2; NOT an acid, turns into a weak acid carbonic acid when combined with water
what is the rxn when CO2 reacts with H20?
CO2 + H20 —— H2CO3 ——— H+ + HCO3
H2CO3= carbonic acid (weak acid)
which enzyme catalyzes the rxn of CO2 and H20 to H2CO3?
carbonic anhydrase
what does H2CO3 dissociate into?
H+ and HCO3 (bicarb)
when carbonic acid dissociates into H and HCO3, what must happen with the H? where does this occur?
it MUST be buffered; occurs in the RBC
the CO2 produced by aerobic metabolism of cells goes where?
from the tissue to the capillary (more specifically the RBC)
Where is CO2 converted to H+ and HCO3?
in the RBC
what happens to H+ and HCO3 once formed in the RBC?
H+ is buffered and HCO3 diffuses out of the RBC into the plasma
where does HCO3 go once diffused into the plasma?
travels to the lungs to be converted back to CO2 (CO2 is then expired)
catabolism of what two things results in production of fixed acids?
proteins and phospholipids
what does being a volatile acid mean?
means that it will be expired in the lungs
which two acids are non volatile?
sulfuric acid (H2SO4) and phosphoric acid (H3PO4)
how do non volatile acids get excreted?
by the kidney
what must first happen to non volatile acids before getting excreted by the kidney?
they must be buffered in the body fluids
how are fixed acids buffered? what does this result in?
bicarb is pulled from the plasma/blood to buffer them in the body fluids (think of HCl and food when moving through the SI); results in loss of bicarb from the serum
what does a volatile acid and bicarb/base buffer form?
CO2 and H2O
how do the kidneys respond to loss of bicarb from buffering a fixed acid? what is the stable bicarb level the kidneys are aiming for?
they promote secretion of H and generate new bicarb; 24
primary disturbance of metabolic acidosis?
decrease in HCO3
normal range for bicarb?
24-31
normal range for anion gap?
8-12
normal range for PCO2?
35-45
normal range for Na?
135-145
normal range for Cl?
98-106
normal range for pH?
7.35-7.45
a decrease in bicarb and what affect on pH AND PCO2 will signal metabolic acidosis?
pH < 7.35 decreased PCO2 (more being ventilated out to bring out alkalosis)
what is the respiratory compensation for metabolic acidosis?
hyperventilation to get decreased PCO2 (<35)
what is the renal compensation of metabolic acidosis?
SLOWER response than resp
secretion of H+ and generation of new bicarb in the alpha intercalated cells
what are the two roles of the kidney on maintaining acid base balance? where do these processes occur?
1) . reabsorption of filtered HCO3 (ONLY occurs in the proximal tubule cells)
2) . excretion of H+ and generation of HCO3 (ONLY occurs in the distal tubule alpha intercalated cells)
why is excretion of H+ accompanied by new production of bicarb?
fixed H+ has to be buffered by bicarb and creation of new bicarb in the alpha intercalated cells occurs to replace those lost stores
we reabsorb filtered HCO3 to maintain a serum bicarb of __-___
24-26
what body problem can alter the balance of reabsorbing filtered bicarb?
volume depletion