What is the most important component in the O2 transport system? ...

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What is the most important component in the O2 transport system?
 
  a. Dissolved O2 in ml/dl
  b. HCO3
  c. Hb
  d. PaO2

Question 2

When O2 uptake by the tissues is abnormally low, as occurs in certain forms of dysoxia, what would you expect to find?
 
  a. Decreased CaO2
  b. Decreased CvO2
  c. Decreased PaO2
  d. Increased CvO2

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Answer to Question 1

ANS: C
Progressive falls in blood hemoglobin content cause large drops in arterial O2 content (CaO2). In fact, a 33 decrease in hemoglobin content (from 15 to 10 g/dl) reduces the CaO2 as much as would a drop in PaO2 from 100 to 40 mm Hg.

Answer to Question 2

ANS: D
Dysoxia is a form of hypoxia in which the cellular uptake of O2 is abnormally decreased. The best example of dysoxia is cyanide poisoning. Cyanide disrupts the intracellular cytochrome oxidase system, thereby preventing cellular use of O2.