acid base Flashcards
when arterial pH is lower than 7.38 it is called
acidemia
and alkalemia if it is higher than 7.42
intracellular pH=
7.2
so more acidic than ECF
Acid production has two forms
Volatile (CO2)
Fixed acid
example for what will generate fixed acid
catabolism of proteins and phospholipids
which AA will generate fixed acid?
sulfur-containing: Met, Cy
what will catabolism of Met, Cy generates?
sulforic acid
what will the catabolism of phospholipids geenerates?
phosphoric acid
which fixed acid can be generated in pathophysiologic states?
B-Hydroxybutyric acid
acetoacetic acid
(also lactic acid when exercise)
Aspirin metabolism will give us which fixed acid?
Salicylic acid
define a Buffer
mixture of a weak acid and its conjugated base
or week base and its conjugated acid
Handerson-Hasselbalch equation
pH = pK + log[A-]/[HA]
reaction made by Carbonic Anhydrase
CO2 + H2O ↔ H2CO3
later will form HCO3- and H+
wht bicarbonate buffer is the most important one?
allows quick adaptation to changes in the pH due to its buffering capacity
acidemia triggers _____ through:
Hyperventilation
through carotid body chemoreceptors to allow expiration of more CO2
urinary tract buffers
phosphate
creatinine
uric acid
(ammonium)
what makes Hemoglobin a buffer?
HgB has 37 His residues that can accept a H+
PaCO2
38-42 mmHg
standart HCO3-
23-25 mM
actual HCO3-
23-25 mM
Buffer base
44-49 mEq/L
base excess
+/- 2.5 mEq/L
kidney function in acid-base balance?
- Bicarbonate reabsorbtion
2. H+ secretion
where does bicarbonate reabsorb in the kidney and how?
PCT
with Na+
what can effect HCO3- reabsorption?
- filtered load (in case of alkalosis -> tubular transport is saturated -> more Bicarbonate excreted)
- ECF volume (increased ECF -> decreased HCO3- reabsorption)
metabolic acidosis is due to
decrease inbicarbonate which can be caused by an increase in fixed acids (there is not enough HCO3- to neutralize them)
or maybe we lost HCO3-
metabolic alkalosis is due to
increased in HCO3-
resoiratory acidosis is due to
Hypoventilation
CO2 retention
decreased pH
resoiratory alkalosis is due to
Hyperventilation
A- form of Bicarbonate buffer is
HCO3-
pK of the HCO3-/CO2 buffer
6.1
