Which of the following conditions leads to tissue hypoxia without alteration of oxygen content of blood? A. CO poisoning
B. Methemoglobin
C. Cyanide poisoning
D. Respiratory acidosis
B. Methemoglobin
C. Cyanide poisoning
D. Respiratory acidosis
Ans. C.
• CO has 200 times greater affinity for Hb, compared to oxygen. Hence, in CO poisoning, 02 cannot bind with Hb and 02 content of blood will decrease.
• Methemoglobin formation is due to poisoning with chlorates, nitrites, or ferricyanides. In methemoglobin, iron is Fe3 instead of Fe2 It cannot combine and transport °2 in normal amounts. 02 content of blood will decrease.
• Respiratory acidosis as a result of hypoventilation will also be associated with hypoxia; 02 content of blood will be less.
• In cyanide poisoning, there is histotoxic hypoxia. 02 content of arterial blood is normal; however, tissues are not able to utilize oxygen.
• CO has 200 times greater affinity for Hb, compared to oxygen. Hence, in CO poisoning, 02 cannot bind with Hb and 02 content of blood will decrease.
• Methemoglobin formation is due to poisoning with chlorates, nitrites, or ferricyanides. In methemoglobin, iron is Fe3 instead of Fe2 It cannot combine and transport °2 in normal amounts. 02 content of blood will decrease.
• Respiratory acidosis as a result of hypoventilation will also be associated with hypoxia; 02 content of blood will be less.
• In cyanide poisoning, there is histotoxic hypoxia. 02 content of arterial blood is normal; however, tissues are not able to utilize oxygen.
