HUMAN ANATOMY AND PHYSIOLOGY

 Description various cells during erythropoiesis:

Haemocytoblast is a big endothelial cell in the bone marrow of 18- 23u size it contains nucleus and a thin rim of basophilic cytoplasm it does not contain any haemoglobin it is the initiating cell which proliferates to give megaloblast 
    megaloblast is of 14-19u size it actively multiplies to form erythroblast it needs vit B12 and folic acid for the multiplication and maturation into erythroblast 
Erythroblast is a cell of 11-17u with fewer mitochondria condensed excentric nucleus and few traces of haemoglobin cytoplasm becomes polychromic 
early erythroblast needs iron copper cobalt manganese and calcium as metals thyroxine and corticosteroid hormones vit c vit B12 folic acid vit B2 nicotinic acid pigments like chlorophyll and bile pigments improve haemoglobination whereas bile salts and the metals named above aid haemoglobin formation indirectly 
                Normoblast: It is of 10-14u size nucleolus disappears and haemoglobin content is increased size of the cell decreases as the maturation advances RNA disappears and the size of cell is finally reduced to 7-8u nucleus also starts disintergrating during this stage.
    Reticulocyte: these are similar to RBC but since they are still in the bone marrrow they are called reticulocytes 
    time taken from haemocytoblast to megaloblast is 7 days whereas from megaloblast to erythrocytes in 2 days 
Essential diet for RBC Formation : First class proteins like milk eggs meat pulses etc are helpful in building chromoproteins and nucleoproteins as well as globin of haemoglobin in RBC vitamin B12 folic acid (pteroylglutamic acid) vit B2 nicotinic acid vit c etc are also essential for erythropoiesis liver bone marrow meat milk pulses etc are good sources of vit B12 leafy vegetables yeast etc give pteroylglutamic acid amala lemon and citrate fruits are good source of vit C 
IRON copper cobalt manganese and calcium are very useful for synthesis of Hb green vegetables are a rich source of iron whereas other metals are needed in traces which are obtained from routine foods 

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