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27 Cards in this Set
- Front
- Back
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Acid (definition)
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substance containing hydrogen ions that can be liberated or released
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Alkali (definition)
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a substance that can accept or trap hydrogen ions
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An acid releases hydrogen as follows:
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H2CO3 -> H+ -> HCO3-
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a base traps hydrogen as follows:
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HCO3- + H+ -> H2CO3
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strong acid vs weak acid
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a strong acid separates completely in solution and releases all of it's H+ ions, a weak acid loses only a few
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Strong base vs weak base
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strong base accepts H+ ions easily, while a weak base accepts H+ ions less readily
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approximate PH of gastric secretions
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1-1.3
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approximate PH of pancreatic secretions
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10
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examples of strongly acid and base body fluids
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Acid: gastric secretions
Base: pancreatic secretions |
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normal serum PH
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7.35 - 7.45
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Acidosis
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excess of H+ ions in ECF and pH falls below 7.35
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Alkalosis
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lack of H+ ions in ECF and pH rises above 7.45
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3 major homeostatic regulators of hydrogen ions
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1) buffer systems
2) respiratory mechanisms 3) renal mechanisms |
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buffer (definition)
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a substance that prevents body fluids from becoming overly acidic or alkaline
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3 buffer systems for pH
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1) carbonic acid-sodium barcarbonate
2) Phosphate buffer system 3) Protein buffer system |
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what is the most important pH buffer system
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carbonic acid-sodium barcabonate buffer system
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how much of the H+ of ECF does the carbonic acid-sodium bicarb system buffer?
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up to 90%
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normal ratio of bicarbonate to carbonic acid
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20:1
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where is the phosphate buffer system active?
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in the intracellular fluids
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what does the phosphate buffer system do?
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it converts alkaline sodium phosphate, a weak base, to acid-sodium phosphate in the kidneys
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Chemical symbol for sodium phosphate
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NaHPO4
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Chemical symbol for acid-sodium phosphate
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NaH2PO4
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What is the protein buffer system?
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a mix of plasma proteins and the globin portion of hemoglobin in RBCs
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How does the protein buffer system work?
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plasma proteins and hgb have chemical groups that can combine with or liberate H+ ions and tend to minimize changes in pH
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How well does the protein buffer system work?
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excellent buffering agents over a wide range of pH values.
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excess H+ ions cross over the plasma membrane of RBCs and bind to the hgb molecules that are plentiful in each RBC
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example of how the protein buffer system can work
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Body reactions at different ph levels...
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< 6.8 = death; 6.8-7.35 = acidosis; 7.35-7.45 = normal; 7.45-7.8 = alkalosis; > 7.8 = death!
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