Life Span:RBC lives in the blood for 3-4 months
Fate of RBC: when RBC gets old becomes flask shaped and breaks off the fragments are swallowed by Reticulo endothelial system (RES) The RES cells of the liver and spleen digest them Hb is broken down into haem and globin protein globin is broken down to its amino acids Liberated iron gets converted to ferritin and haemosiderin this goes to build up new Hb remaining haem gets converted to bilirubin which is oxidised to biliverdin these pigments are converted to urobilinogen by bacterial fermentation in the large intestine some urobilinogen is reabsorbed and excreted in urine as urobilinogen the rest is exreted as stercobilinogen and stercobiline giving brown colour to faeces
haemoglobin (Hb) is the colouring matter of RBC it is the respiratory pigment found in the red blood corpuscles (RBC) of the blood chemically it is a type of conjugated protein consisting of globin which is conjugated with a metalloporphyrin haem Haem consists of 4 pyrrole groups linked to non ferrous group and joined to each other by methine (CH) groups Globin helps haem to keep iron in ferrous state and to combine loosely and reversibly with molecular oxygen
Synthesis of Haemoglobin :
formation of haemoglobin occurs in bone marrow first class proteins containing histidine leucine and phenylalanine stimulate haemoglobin formation diet containing heart spleen kidneys and some fruits aid Hb formation as they are rich in these amino acids iron is the main metal of Hb others are copper manganese and cobalt copper acts as a catalyst and cobalt is an important constituent of Vit B12 which is red in colour because of the cobalt it incorporates
Prophyrins III that is found in nature is also useful for synthesis of Hb porphyrin is built up from amino acid in a complicated way
Thyroxine hormone also plays an important role in Hb synthesis vitamin B12 folic acid nicotonic acid riboflavin (vit B2) have their own role in Hb formation
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