Phosgene gas exposure would reduce the amount of O2 available for gas transport
ID: 3513029 • Letter: P
Question
Phosgene gas exposure would reduce the amount of O2 available for gas transport in the blood, as the efficiency of pulmonary gas exchange would decrease due to the damage caused to the respiratory membrane. How would you expect the affinity of hemoglobin for oxygen to change in the blood if the PO2 level was diminished by this damage?
After exposure to phosgene gas, the partial pressures of both O2 and CO2 would be altered in the blood and tissues, because the mechanism for moving these gases in and out of the body has been compromised.
(a) Define both pulmonary gas exchange and tissue gas exchange.
(b) After severe exposure to phosgene, what would you expect to find if you measured the partial pressure of oxygen (PO2) and carbon dioxide (PCO2) in the alveoli, the blood plasma, and the cells of the tissues?
a. Hemoglobin affinity for oxygen would become stronger, and less oxygen would be unloaded into the tissues.Explanation / Answer
Ans.
The choice is (b), due to diminished pO2, the haemoglobin affinity for oxygen would become weaker and less oxygen would be unloaded into the tissues.
Ans.(a).
Pulmonary gas exchange: It is called as external respiration. Pulmonary gas exchange takes place in lung between the alveoli and blood. Here CO2 is removed from the blood to atmosphere and O2 is taken in the blood from atmosphere.
Tissue gas exchange: It is called as internal respiration or peripheral gaseous exchange where there is gaseous exchange between blood and tissues. Here the oxygen from haemoglobin is uploaded to the tissues and carbon di oxide from tissues goes into the blood.
Ans.(b)
Alveoli: pO2 is more( not more in real sense but since some gaseous exchange will be there, the pO2 will be somewhat better in alveoli as compared to other parts), pCO2 is less(again same reason, not less in real sense but due to some gaseous exchange still occurring at alveoli level, pCO2 will be less as compared to other places).
Blood plasma: pO2 is lessas compared to alveoli but more as compared to cell tissues, pCO2 is more as compared to alveoli but less as compare to cell tissues.
Cells of tissues: pO2 is less as compared to alveoli and blood, pCO2 is more as compared to alveoli and blood.