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11 Cards in this Set
- Front
- Back
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Chloride depletion and K+ depletion, when marked stimulate H+ secretion into the renal tubule lumen, resulting in a metabolic alkalosis. TRUE/FALSE
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TRUE.
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Does sodium depletion cause H+ loss?
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Yes. Na+ depletion results not only in increased sodium reabsorption, but also in increased H+ secretion into the renal tubules, since H+ exchanges for sodium during the increased sodium reabsorption.
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What are the ingredients of a buffering system?
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These include a mixture of molecules that prevent the pH from changing significantly on adding acid or base. This consists of the mixture of a weak acid and its conjugate base.
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Explain this equation?
HB(weak acid)---H+(strong acid) + B-(conjugate weak base). |
Addition to the mixture of a strong acid does not drastically lower the pH, because the weak base partly neutralizes the added acid. The reaction moves to the left, reducing the amount of added H+.
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What is the bicarbonate buffer system?
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This is the main extracellular buffering system and the one generally thought of in considering clinical matters of acid base balance.
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What are the main intracellular buffers?
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These are proteins and phosphates. the weak acid and conjugate base are H2CO3 and HCO3- respectively, which interact in the general reaction:
H2CO3---H+ + HCO3-. |
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Because the amount of undissociated H2CO3 is minimal, the weak acid, may be considered to be CO2: Write the equation that depicts this.
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CO2+H2O--H2CO3--H+ +HCO3-.
The addition of a strong acid(H+) will move the reaction to the left, toward CO2 and H2O, rather than leaving an abundance of H+, floating around the bloodstream. This leftward shift will blunt the effect of the added H+ and the result will be less acidic than would otherwise be the case. |
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Regarding the above equation, what would happen with the addition of a strong base?
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This will move the reaction to the right, because the H+ ion on the right disappears;CO2 and H2O combine to form H+ and HCO3-, thereby replenishing some H+ and rendering the final result less alkaline than it would otherwise be.
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Do the lungs affect CO2 concentration?
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yes. They do this by the exhalation of excess CO2.The lungs influence CO2 levels through brain stem respiratory centers that respond indirectly to alterations in CO2 levels.
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What is the result of increased blood CO2 or H+ levels?
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The stimulation of the brain stem respiratory center to increase respiration, to blow off CO2 and decrease blood acidity.
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What are the main stimuli to the brain stem neurons?
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H+, but H+ does not cross the blood brain barrier easily. CO2 does and then reacts with water to produce the necessary H+ ions, which stimulate the respiratory center cells to increase respiration and blow off CO2.
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