Question
A 36-year-old male is brought to the emergency department after a motor vehicle accident. Examination showed a large bruise over his anterior chest. Several days later, the bruise has a greenish color that is best explained by the action of:
| A. |
Ferrochelatase
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| B. |
Uroporphyrinogen decarboxylase
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| C. |
Heme oxygenase
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| D. |
Bilirubin glucuronyl transferase
|
Show Answer
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Correct Answer � C
Explanation
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|
Ans. C. Heme oxygenase
Explanation: The patient shows the signs of a resolving hematoma after a traumatic injury.
Heme oxygenase converts heme to biliverdin, a greenish pigment that causes the greenish color to develop in ecchymoses and hematomas several days after an injury. Lysis of erythrocytes in ecchymoses and hematomas causes release of hemoglobin into the soft tissues, and the heme molecule is ultimately degraded to bilirubin. After red cells reach their life span, they are phagocytosed and degraded by the cells of the reticuloendothelial system. These cells cleave globin into its constituent amino acids and return iron to the body’s iron stores. Heme is then cleaved to produce carbon dioxide and biliverdin, which is then reduced to bilirubin and transported to the liver bound to albumin.
