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10 Cards in this Set
- Front
- Back
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What are the 2 major types of inherited disorders of Hb in humans?
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1. Hemoglobinopathies
2. Thalassemias |
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What are the differences between the two?
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In Hbopathies, abnormal polypeptide chains are produced.
In Thalassemias, the chains are normal in structure but produced in in decreased amounts or absent because of defects in the regulatory portion of the globin genes. |
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These disorders are identified by letter; Hb C, E, I, J, S, etc. TRUE/FALSE
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True. In Hb S, the alpha chains are normal but the beta chains are not, because among the 146 AA residues in each beta polypeptide chain, one glutamic acid residue has been replaced by a valine residue.
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When an abnormal gene inherited from one parent dictates formation of an abnormal Hb(heterozygous individual), half of the circulating Hb is abnormal and half is normal. TRUE/FALSE
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TRUE. many of the abnormal Hb are harmless, however some have abnormal O2 equilibriums. Ex; Hb S polymerases at low O2 tensions, and this causes the red cells to become sickle shaped, hemolyze and form obstructive aggregates.
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heterozygous individuals have the sickle cell trait and rarely have severe symptoms. TRUE/FALSE
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TRUE. Homozygous develop full disease.
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Sickle cell confers resistance to one type of malaria. TRUE/FALSE
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TRUE.
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What is Hb F?
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Hb F has the ability to lessen the polymerization of deoxygenated Hb S and hydroxyurea causes Hb F to be produced in children and adults. It has been used with some success for sickle cell treatment.
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What is the normal Hb content of blood/
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It is app. 16g/dL in men and 14g/dL in womwn, all of it in RBC.
In the body of a 70kg man there is app. 900g of Hb, and 0.3 g of Hb is destroyed and the same amount is synthesized every hour. |
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What happens to old RBC that are destroyed?
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When they are destroyed in tissue macrophage system, the globin portion of the Hb molecule is split off and the heme is converted to biliverdin.
The enzyme involved is a subtype of heme oxygenase and CO is formed in the process. CO may be an intercellular messenger. |
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In humans, most of the biliverdin is converted to bilirubin and excreted in the bile. TRUE/FALSE
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TRUE.
Exposure of the skin to white light converts bilirubin to lumirubin which has a shorter half-life.(phototherapy) |
