What is the correct relationship between red cells' affinity for ...

[craiczarry]

What is the correct relationship between red cells' affinity for oxygen and red cell production?
 
  a. When affinity is low, more oxygen is released and the body compensates by making red cells larger.
  b. When affinity is low, less oxygen is released and the body compensates by increasing erythropoietin and making more red cells.
  c. When affinity is high, less oxygen is released and the body compensates by increasing erythropoietin and making more red cells.
  d. When affinity is high, more oxygen is released and fewer red cells are needed.

Question 2

Which of the following is a typical finding in patients with Hb M?
 
  a. Severe anemia requiring repeated blood transfusions
  b. Elevated levels of ferrous iron (Fe2+) in the red cells
  c. Presence of Heinz bodies on Wright-stained blood film
  d. Elevated methemoglobin

[akpaschal]

Answer to Question 1

ANS: C
When hemoglobin's oxygen affinity is high, less oxygen is released to tissue. The normal physiologic response to less oxygen delivery is to increase erythropoietin and make more red cells.

Answer to Question 2

ANS: D
Methemoglobin is elevated in Hb M. Affected persons may have 30 to 50 methemoglobin (Fe2+). The amino acid substitutions found in the various Hb Ms cause heme iron to autooxidize, forming methemoglobin. Heinz bodies may be present, but they are not visible with a Wright stain.

[craiczarry]

Excellent

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