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28 Cards in this Set
- Front
- Back
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Oxygen transport |
-Dissolved -Combined with hemoglobin |
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Dissolved O2 |
-Obeys Henry's Law (C(O2) = a O2 x PO2) -Can diffuse through membranes -3 mL of O2 in a liter of blood (15 mL /min) -Hyperbaric oxygen treatment |
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Oxygen combined with Hb |
-Difference between total concentration and dissolved -Increases rapidly to 50 mmHg then flattens
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O2 capacity |
-Max O2 -dependent on Hemoglobin - all available binding sites occupied -20.1 mL O2 / 100 mL of blood is normal |
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Equilibrium between dissolved and chemically bounded |
-Partial pressure of oxygen is produced only by the dissolved oxygen - the higher the PO2 dissolved the greater will be bound to Hb -As O2 diffuses the PO2 falls and bounded O2 are set free -Equilibrium achieved by equality of partial pressures |
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O2 saturation of Hb |
-percentage of available hemoglobin binding sites that have O2 attached -O2 bound to Hb / O2 capacity -If PO2 = 100mmHg saturation = 98% ; if PO2 is 40 mmHg saturation = 75% |
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P50 |
-pressure When O2 saturation is at 50% -usually 27 mmHg -Used to determine a shift |
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Saturation curve |
-Flat upper part - Even if Alveolar gas falls slightly, loading of blood is mildly affected -Steep lower part- Means peripheral tissue can withdraw large amounts of O2 for only a small drop in PO2 (Keeps driving pressure up) |
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Decrease PO2 |
Will cause a reduction in both O2 saturation and concentration
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Decrease in Hemoglobin |
Will cause a decrease in O2 concentration but not saturation |
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O2 affinity and delivery |
-If P50 is less than 27mmHg, hemoglobin has higher affinity for oxygen and curve shifts to left -rightward shift = lower affinity |
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Hydrogen ion |
High H+ shifts curve to the right |
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Carbon Dioxide |
High PCO2 shifts curve to the right -Bohr effect |
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Bohr effect |
-Increase in PCO2, increases H+ which reduces O2 binding affinity -Higher O2 partial pressure needed |
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Temperature |
Higher temp decreases O2 affinity
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2,3 DPG or BPG |
-Increase, shifts curve to right -helps in high altitudes and chronic lung disease |
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Fetal hemoglobin |
Higher affinity than adult |
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Carbon monoxide poisoning |
-Carboxyhemoglobin -Carbon monoxide has much higher affinity for Hb than oxygen (240 times) -.1% of CO will take 50% of Hb binding sites -Also shifts curve to left so unloading of oxygen is hindered -O2 concentration reduced but PO2 remains the same -Hyperbaric can overcome |
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Methemoglobin |
-Fe2+--->Fe3+ -methemoglobin reductase converts back to normal -can't bind oxygen |
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CO2 transport |
- carried in the blood in 3 forms -Dissolved -Bicarbonate -Carbamino |
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Dissolved CO2 |
-Obeys Henry's law but is dissolved 20 times more than oxygen -10% |
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Bicarbonate |
-CO2 + H2O <----> H+ + HCO3- -Fast in red blood cells because of carbonic anhydrase -HCO3- is transported to plasma with exchange of Cl- -70% |
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Carbamino |
-CO2 + amino groups in proteins -Binds to globin with high affinity, so the unloading of O2 facilitates loading of CO2 -20% |
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CO2 disassociation curve |
-PCO2 vs CO2 concentration -Much steeper than O2 disassociation curve -Does not undergoes saturation, so there is no maximal value (increase with PCO2) |
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H+ |
-Increase causes decrease in concentration of CO2 -Curve shifted to right |
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Temperature |
-Increase releases CO2 -Shift to right |
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Haldane effect |
-CO2 loading in tissue and unloading in lung -O2 causes shift to the right
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Bohr effect |
-O2 loading in lung and unloading in tissue -CO2 causes shift to right |
