Adult hemoglobin appears in fetus at thegestational age of (in weeks)
A. 5thB. 10th
C. 15th
D. 20th
E. 25th
Ans. (E)
25th
• Haematopoiesis is demonstrated in the embryonic phase in the yolk sac by the 14thday. By 10thweek, the liver becomes the major site,, and after that gradually bone marrow become the major site of red cell production.
• Between the 5-8weeks, the embryo manufactures some additional haemoglobin : Hb Gower-1, Hb Gower-2 and Hb Portland. At 10-11 wks. HbF (Fetal Hb) predominate.
• Haematopoiesis is demonstrated in the embryonic phase in the yolk sac by the 14thday. By 10thweek, the liver becomes the major site,, and after that gradually bone marrow become the major site of red cell production.
• Between the 5-8weeks, the embryo manufactures some additional haemoglobin : Hb Gower-1, Hb Gower-2 and Hb Portland. At 10-11 wks. HbF (Fetal Hb) predominate.
*
From 24 weeks onwards adult type of hemoglobin appears in fetus. But during
first half, hemoglobin is fetal type (α2v2) and at term
about 75-80% of total hemoglobin is fetal type.
• Cord blood level of Iron, ferritin, vit. B12, folic acid are higher than maternal blood.
HbF : α2β2
HbF : α2γ2
• Cord blood level of Iron, ferritin, vit. B12, folic acid are higher than maternal blood.
HbF : α2β2
HbF : α2γ2
HbA2
: α2θ2
