Basics of Acids and Bases
What is the standard pH of arterial blood?
What is the standard pH of venous blood?
pH = -log [H+]
What equation does pH stand for?
Kw = [H+] * [OH-] = 10^-14
What equation describes Kw?
Ka = ([H+][A-]) / [HA]
What equation describes Ka?
pH = pKa + log ([A-] / [HA])
Describe the Henderson Hasselbach equation
What buffers interstitial fluid?
What buffers extracellular fluid, especially the blood?
What buffers erythocytes?
Carbonic Anhydrase, non-enzymatically
What catalyzes bicarbonate buffering in RBCs and the kidneys? What about in the plasma?
H+ + HCO3- = H2CO3 = H2O + CO2 (respirated)
Describe the rxns of bicarbonate under increasing acidity
OH- + H2CO3- = H2O + HCO3-
Describe the rxns of bicarbonate under decreasing acidity
Increased plasma K+ as RBCs exchange K+ for H+
What happens to plasma potassium during acidemia?
Decreased plasma K+ as RBCs exchange H+ for K+
What happens to plasma potassium during alkalemia?
What signal do the kidneys use to regulate RBC production in the bone marrow?
Maintain bicarbonate, excrete H+
What functions do the kidneys perform to buffer the blood?
70% dissolves in water in equilibrium w/ bicarbonate, 20% is carried as a carbamino group on hemoglobin, 10% is dissolved in the plasma
Once CO2 is produced by metabolism in the tissue, what is its distribution in various transport systems?
Oxygenated blood has a lower affinity for CO2 than deoxygenated blood
What is the Haldane effect?
Anion Gap = [Na+] - ([Cl-] + [HCO3-])
What is the equation for the anion gap in the blood?
Range 8-16, Mean 12
What is the normal range of the anion gap?
The presence of unaccounted anions/increased HCO3-
What does a high anion gap indicate?
2 x Na+(mEq/L) + glucose(mg/dL)/18 + BUN (mg/dL)/2.8
2 x [Na+] + [glucose] + [urea] (all in mmol/L)
What is the equation for blood osmolality?