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Increased ratio of base to acid
Alkalosis
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Decreased ratio of base to acid
Acidosis
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pH of blood equals ...
- hydrogen ion concentration
- ratio of bicarb (base) to dissolved CO2 (acid)
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What is the significance of maintaining blood pH within a very narrow range?
What effect does it have on cell function and why?
- Any change in pH can have damaging effects on cell structures and cell functions
- Can damage cell proteins
- Low pH = cell death
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Bicarbonate-Carbon Dioxide buffer system
CO2 + H2O <--> H2CO3 <--> H+ + HCO3-
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Review factors affecting the oxyhemoglobin curve. (p.3)
- Relationship between hemoglobin saturation and pO2.
- pO2:
- = major factor determining how much oxygen is available for hemoglobin to carry
- = greater pO2 = more Hgb saturated with O2
- = lower pO2 = less Hgb saturated
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What factors cause shift to the RIGHT on the oxyhemoglobin curve?
- decreased affinity of O2 for hemoglobin
- 1) decreased pH
- 2) increased 2,3 DPG
- 3) increased temperature
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Shift to the RIGHT - decreased pH
- blood is acidic
- increased CO and H+ alters hemoglobin configuration
- reduces O2 binding to heme on Hgb
- Net effect = hemoglobin releases O2
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Shift to the RIGHT - increased 2,3 DPG
- found in RBCs
- helps unload O2
- binds with hemoglobin, releasing O2
- seen with:
- = increased metabolism
- = hypoxia
- = anemia
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Shift to the RIGHT - increased temperature
increased metabolic state
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What factors cause shift to the LEFT on the oxyhemoglobin curve?
- increased affinity of O2 for hemoglobin
- 1) increased pH
- 2) carbon monoxide
- 3) decreased 2,3 DPG
- 4) glycosylated hemoglobin (HgbA1c)
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Shift to the LEFT - increased pH
- hemoglobin holds on to O2
- can cause:
- = respiratory distress
- = tissue hypoxia - if hemoglobin does not release O2, O2 is not available to cells
- = compensatory hyperventilation
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Shift to the LEFT - carbon monoxide
- has 215 times the affinity that O2 has for hemoglobin
- CO combines with same amount of Hgb as O2 when CO partial pressure is 215 times lower
- if Hgb exposed to small amounts of CO, unable to carry O2
- pO2 may appear normal
- Hgb-O2 content drastically reduced = cell hypoxia
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Shift to the LEFT - decreased 2,3 DPG
- example = blood transfusion
- due to transfusion, blood is depleted of 2,3 DPG
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Shift to the LEFT - glycosylated hemoglobin (HgbA1c)
- measure and monitor of diabetes
- increased blood glucose = more glucose in RBCs and binds with hemoglobin causing it to hold on to O2
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What effect would these shifts have on affinity of hemoglobin for oxygen?
- RIGHT = decreased affinity of O2 for Hgb
- LEFT = increased affinity of O2 for Hgb
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What effect does lactic acidosis have on the oxyhemoglobin curve?
- decreased pH = RIGHT
- decreased 2,3 DPG = LEFT
- end result = normal curve
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