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25 Cards in this Set
- Front
- Back
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What is the equation for pH?
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pH= -log [H+]
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What is normal blood PH?
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7.4
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What is the normal blood PH range?
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7.37- 7.42
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What is the normal level of hydrogen ions in the blood
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40 nEq/L (40*10^-9, or 4X 10^-8)
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What is the source of volatile acid? handled by?
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this is created by respiratory CO2, handled almost entirely by the lungs
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What are the sources of fixed H+ creation? how much?
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50 mEq/day
produced by gluconeogenic use of AA's Sulfuric acid from AA catabolism |
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What is the henderson hasselbalch equation?
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pH=pK + log A-/HA
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What is the respiratory system equilibrum equation (not a true equation, be an expansion of l'chatliers principle)
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H2O+CO2 <-> H2CO3 <-> H+ + HCO3-
this is used to show how adding or subtracting H+ or CO2 will shift equilibrium |
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What is the first line of defense against pH changes?
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the buffer system
bicarbonate buffer system being the most important in the ECF |
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Where is the most effective buffering zone?
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+/- one pH unit from pK
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What is the PKA of bicarbonate?
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6.1
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What buffer has the most buffering capacity in the blood, second most?
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MOST: bicarbonate 53%
2nd: hemoglobin |
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What are the two primary intracellular buffers?
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Proteins
phosphate both Pka's are close to 7.4 |
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How does bone affect pH?
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this can take up H+ in exchange for Na+ and K+
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What is the Equation for the bicarbonate buffer system?
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pH= 6.1 + Log (HCO3-)/ (.03 X Pco2))
this uses the .03X P co2 to approximate H+ concentration (using H2CO3-> H+ and HCO3- in the equation overall) |
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Can buffers return pH to normal?
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NO they cannot- they only minimize change
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How does pH regulation occur?
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this happens in the lungs and the kidneys, called compensation.
the lungs and kidney regulate CO2 and HCO3- so that the ratio stays near 20 |
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What are changes in HCO3- concentration called?
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METABOLIC disturbances
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What are changes in CO2 levels called?
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RESPIRATORY disturbances
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What compensates for loss of gain of HCO3? (metabolic disturbance)
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this is compensated by the kidneys AND lungs
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What compensates for changes in CO2 levels? (respiratory disturbances)
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this must be compensated by the kidneys
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What happens during Metabolic acidosis?
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plasma HCO3- decreases
(pH=6.1 + Log (HCO3-/ .03X Pco2)) (low HCO3-, will decrease this log, lowering pH) Metabolic can be compensated by both kidneys and lungs. lungs increase vent rate to expel co2, and kidneys produce more HCO3- |
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What happens during metabolic alkalosis?
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Plasma HCO3 increases
this drives pH up! respiratory system response by reducing vent rate to retain CO2, kidney excretes excess HCO3- |
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What happens during respiratory acidosis?
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this is an increase in PCO2, caused by decreased ventiation
kidneys make more HCO3- and excrete H+ |
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what happens during respiratory alkalosis?
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this drives pH up, due to low Pco2 from rapid breathing
causes kidneys to excrete HCO3- |
