Unit 9

  1. Does acid have more or less ions?
    More H+ ions
  2. Does base have more or less ions?
    Fewer H+ ions in a solution that can accept H+ ions
  3. Why is acid-base balance important?
    • Cell membrane integrity
    • Cellular enzymatic speed
    • Speed at which interactions in body happen
  4. Where do acids come from ?
    • Metabolic processes
    • NOrmal by-product of nutrient absorption and metabolism
    • Buffered by body systems
  5. Where do bases come from?
    • chemicals that can donate or accept H+ ions
    • Bicarb is the base used to counteract acidosis
    • production of bicarb occurs in the kidneys
    • bicarb is produced in response to an acid-base imbalance
  6. What is a buffering system?
    • absorbs or releases H+ ions to correct imbalances in acid-base balance
    • regulates H+ ion concentration by maintaining ration of 20 parts bicarb to one part carbonic acid
    • this concentration is measured by the PH level
  7. What is arterial pH?
    • Indirectly measure H+ ions
    • H+ ion =>acid=<pH
    • H+ ion =<acid >alkaline=>pH
    • reflects the balance between CO2 and HCO3
    • Above 7.45 = alkaline (alkalosis)
    • Below 7.35 =Acid (acidosis)
    • Normal between 7.35-7.45
  8. Where does bicarb come from?
  9. Where does CO2 come from ?
  10. What are acid-base regulators?
    Chemical, biological, physiological
  11. Explain chemical regulation
    Carbonic acid is first to react, happens in seconds
  12. Explain biological regulation
    • Hydrogen ions absorbed & released by cells
    • after chemical buffering
    • slow process
    • must exchange with another + ion or be accompanied by ions of opposite charge
    • K+
    • Hemoglobin-oxyhemoglobin system
    • Chloride shift
  13. Explain physiological regulation
    • Kidneys
    • regulation takes hours to days to occur
    • reabsorbs bicarb when acidosis occurs
    • excretes bicarb when alkaloisis occurs
    • also uses PO4 ion to form phosphoric acid to excrete H+ ions
    • Use another mechanism, the ammonia mechanism to regulate balance
    • Amino acids in renal tubules
    • Ammonia + H+ =(ammonium) = excreted through urine
  14. Explain physiological regulation in regard to lungs
    • Lungs
    • response within minutes
    • increased H+ and CO2 = increased respirations
    • metabolic acicosis = >respirations = more CO2 excreted through exhalantion=< acidosis
    • Metabolic alkalosis=<respirations = more CO2 retained =>acid
    • CO2 + H2O <> H2CO3 carbonic acid
  15. What is a normal pH?
  16. What is a normal PaCO2 (partial pressure depth of ventilation)?
    35-45 mmHg
  17. What is a normal PaO2?
    80-95 mmHg
  18. What is a normal O2 saturation?
  19. What is normal base excess?
    +/- 2
  20. What is normal HCo3?
    22-26 mEq/L
  21. What do kidneys do for acid/base buffer?
    Excrete to obtain buffer for extracellular fluid
  22. Hyperventilation with PaCO2
    Below 35 mmHg
  23. Hypoventilation with PaCO2
    increased 45 mmHg
  24. Explain respiratory acidosis and when it occurs
    H2CO3 excess, During hypoventilation, pH is decreased, CO2 is increased, Carbonic acid is increased
  25. Explain respiratory alkalosis and when it occurs
    Hyperventilation, asthma, anxiety, Increased pH, PaCO2 decreased, CO2 decreased, H2CO3 deficit
  26. Explain metabolic acidosis and when it occurs
    Decreased bicarb, happens if too much diarrhea or renal disease,reversed by lungs, HCO2 deficit
  27. Explain metabolic alkalosis and when it occurs
    Increased bicarb, HCO3 excess, due to vomiting, too much GI suctioning, K+ deficiency
  28. What happens if you have too much CO2?
    Acidosis occurs
  29. What if you have not enough CO2?
    Alkalosis occurs
  30. what happens if you hyperventilate?
    Alkalosis occurs
  31. What happens if you have hypoventilation?
    Acidosis occurs
  32. When does acid-base balance occur?
    When acid/base excretion=acid/base production
  33. What does acid/base balance do?
    Maintains cellular integrity, speeds up cellular enzymatic processes
  34. What is acid/base regulated by
    Chemical, biological and physiological processes
  35. What is the first line of defense for regulation?
    The chemical buffering system
  36. what two organs does regulation happen through?
    biologic and physiologic of lungs and kidneys
  37. What happens if you have increased HCO3 if it is above 26?
    Alkalosis (kidneys)
  38. What happens if you have decreased HCO3 if it is below 22?
    Acidosis (kidneys)
  39. What happens if you have increased PCO2 above 45?
    Acidosis (lungs)
  40. What happens if you have decreased PCO2 if it is below 35?
    Alkalosis (lungs)
  41. If there are changes in the kidneys what process is it?
  42. If there are changes in the lungs what process is it?
  43. If the pH and HCO3 are going in the same direction what process is it?
    Metaboic (kidneys)
  44. If pH and CO2 are in opposite directions what process is it?
    Respiratory (lungs)
  45. Explain the chemical formula for acid/base reactions
    • HCl + NaHCO3 >< H2CO3 + NaCl
    • hydrochloric acid + sodium bicarb >< carbonic acid + sodium chloride
    • strong acid + strong buffer base >< carbonic acid + sodium chloride
  46. what are the regulatory systems that control pH balance?
    • 1. Buffer system (chemical regulators)
    • 2. Lungs (physiologic regulator)
    • 3. Cells (biologic regulator)
    • 4. Kidneys (physiologic regulator)
  47. Explain the buffer system that controls pH balance
    • Chemicals that can donate or accept H+ ions
    • Regulates H+ ion concentration by maintaining ration of 20 parts bicarb base to one part carbonic acid
    • Reacts immediately
    • Disadvantage:cannot sustain
  48. Explain how the lungs balance pH
    • Controls the H2CO3 (carbonic acid) component of the HCO3/H2CO3 buffer system. Regulates carbonic acid level by alterating rate & depth of respirations
    • If you have too much acid (excess CO2) respiratory rate & depth increases enabling "blowing off" CO2
    • Rapid regulators, within minutes
    • Controls CO2 content of ECF by adjusting ventilation in response to amount of CO2 in blood
  49. Explain how the cells balance pH
    • capable of admitting or releasing excess H+ ions
    • Slow regulators
    • whenever excess H+ ions cross cell membranes must be either exchanged for ions of same charge or accompanied by ions of opposite charge
  50. Explain how kidneys balance pH
    • Regulates HCo3 (bicarb) in HCO3/H2CO3 buffer system
    • Also eliminates metabolic acid (lungs regulate carbonic acid)
    • Kidneys alter rate of excretion of H+ &
    • HCO3 in urine
    • Slowest of all regulating systems, takes few hours to several days
Card Set
Unit 9