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17 Cards in this Set
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1) What are the volumes of gases in air relatively? What unit used to measure? 2) What is the Dalton's law? s5,6 |
1) Partial pressue N> O > CO2 > other 2) Total atmospheric pressure = sum of partial pressures Patm = PO2 + PN2, PCO2 |
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1) How to calculate partial pressure? 2) What other factor important in overall pressure in the lungs? s6 |
1) Partial pressure = fractional conc * total pressure e.g. PO2 = FO2 * Patm = 21% * 760 mmHg = 159.6 mmHg 2) Air is humidified, water vapour pressure contributes to overall pressure |
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1) Explain changes in partial pressure through circulation. s8 |
1) Indicates how diffusion happens. e.g. lower pressure of O2, and higher CO2 in veins as they are deox, so O2 flows from alveoli into blood and some CO2 into alveoli, until they are at equilibrium with each other. Same principle when diffusing to tissues |
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1) What is Fick's law of diffusion? s10 |
1) Gas transfer = (k * partial pressure gradient) / wall thickness K = solubility of gas in alveolar membrane Lower thickness, more transfer |
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What happens in these conditions 1) Emphysema (destruction of alveoli) 2) Pulmonary edema 3) Asthma s11,12 |
1) If have emphysema (destruction of alveoli), diffusion would be same but lower pressure, because less SA for gas exchange 2) Fluid accumulating in ISF. Distance between alveoli and capillaries larger, thicker membrane, lower diffusion 3) Constriction of bronchioles and increaed airway resistance, decrease gradient pressure and reduce gas exchange |
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1) When oxygen is carried from alveoli to arterial blood, in what forms and what proportions is it carried? what volumes? s14 |
1) 2%< dissolved in plasma, 3 mL O2/L of blood >98% carried in red blood cells, 197 mL O2/L of blood O2 + Hb -> Hb.O2 Goes back to O2 form when diffusing into tissue |
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1) What is the hematocrit s15 |
1) Blood test that measures the percentage of RBC in blood volume 2) perfomed if signs of anemia, diet deficiency, leukemia 3) 40-50% males, 36-44% females 4) Low: anemia, bleeding, leukemia, malnutrition. More High: congenital heart disease, dehydration, hypoxia, pulmonary fibrosis -> more hemo to compensate for O2 lack |
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1) Describe the hemoglobin structure 2) What is the difference between Oxyhemoglobin and Deoxyhemoglobin in terms of wavelength absorption s16-19 |
1) 4 globin units (heme groups), central iron atom binds to O2. 2) Red not absorbed by HbO, so it appears red. Infrared wavelength absorbed by HbO. |
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1) Describe the Oxygen-hemoglobin dissociation curve. 2) How is the curve affected by lower pH, high temperature, higher pCO2, called the Bohr effect. s20 |
1) -> At lung level, 98% of Hb saturated with O2. -> At tissue level, 75% of Hb saturated, 25% released in tissues. 2) Shifts to the right, more oxygen released -> The Bohr effect. |
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1) How do you get carboxyhemoglobin and what happens. How to treat? 2) What is 2,3-DPG s22-23 |
1) Combustion of organic materials produces carbon monoxide, binds to Hb to make carboxyHb. Much higher affinity for CO and O2. CO increases Hb affinity for oxygen, shifting curve to left and releasing less O2. -> Can treat with 100 O2 air, or hyperbaric chamber 2) an intermediate in the metabolic pathway that converts glucose to energy. Changes affinity of Hb for oxygen. High levels shift to the right. |
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1) What is the difference between fetal and maternal Hb affinity. s24 |
1) Fetal Hb has greater affinity for O2 than maternal Hb. 2-3 has less affinity for fetal hemoglobin. So maternal Hb has curve shifted to right. |
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1) What are the 3 forms of CO2 in plasma and erythrocytes s27 |
1) dissolved CO2 in the plasma, Plasma HCO3, protein compounds (carbamino) |
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1) What are the storage forms of CO2 in the veins 2) What happens when transferring into lung? s28 |
1) As it comes from tissues, 7% dissolved in plasma. -> Some combine with Hb in RBC, stored as HbCO2 (23%) -> Some combine with H2O, as CA (carbonic anhydrase) turns them into HCO3 (70%) 2) Reverse of the reactions, as they dissolve into the lungs. |
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1) What happens in respiratory acidosis? s30 |
1) -> Unconscious and probs overdose of narcotics -> lower pH, Higher PCO2, higher [HCO3-] -> Hypoventilation, narcotic induced respiratory depression, diseases of the airways, severe obesity restricting lung expansion. -> Treatment: mechanically assisted ventilation and reversal of narcotic effect |
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1) What happens to O2 consumption when you exercise 2) What is VO2 max and how is it measured? s33 |
1) Get high level of CO2, so it stimulates higher breathing. O2 consumption increases. Carotid bodies trigger ventilation, and sensors in muscle systems have roles as well. Ventilation increases to match O2 needs. Still high few seconds after exercise stops. 2) Highest rate of oxygen consumption possible during maximal exercise. Using maximal effort on treadmill, oxygen levels measured using open circuit spirometry |
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1) How can you improve O2 transport in exercise? s36 |
1) Erythropoietin (EPO): glycoprotein hormone controlling RBC production. Training in altitude or hypobaric chamber: Increases RBC production and muscle metabolism, since trained in low O2 condition. Blood doping or transfusion: increase number of RBCs. |
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1) How do you get an abrupt increase in ventilation? s37 |
1) -> Psychic stimuli (anticipation of stimulus) -> Simultaneous cortical motor activation of the skeletal muscles and respiratory centres. -> Excitatory impulses from proprioceptors in moving muscles, tendons, joints to respiratory centres. |
