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Human Body
Normal blood contains approximately :
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Red cells 5 x 1012 per litre White cells 8 x 109 Platelets 250×109
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Red Blood Cells (Erythrocytes)-these are small flattened bi-concave discs. 3000 of them would be needed to measure an inch. It contains a red pigment, haemoglobin and the huge masses of red cells, hundreds of millions in each drop that together give blood its rich red colour. The shape and structure of these cells represent an extreme of adaptation for its function. They are the gas carriers of the body.
They should be correctly called corpuscles rather than cells, because they have no nucleus but they are often called red cells.
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There are five million red cells per cubic milimeter. Every second three million cells die and equal number of them are born. In the embryo, red cells are formed in the liver, spleen and bone-narrow. At some time before birth, the liver and spleen shut down their red cells production, and the function is taken over entirely by the bone-marrow. A red cell has an average life-span of 120 days during which it makes 300,000 trips, travels more than 1000 km., carrying three quadrillion molecules of oxygen.1
Jain Education International
Haemoglobin has a strong affinity for oxygen and when they come into contact the oxygen is taken up, forming oxyhaemoglobin. This process normally takes place in the lungs. Oxygenated arterial blood has a bright red colour while that in the veins, having lost its oxygen, has a bluishpurple hue.
Haemoglobin of the red cells is an iron containing pigment called haem, combined with a protein, globin. Total amount of iron in the haemoglobin of all the red cells is about 3 grams. But it is priceless, as one cannot live
without it. A continual intake of iron in diet is essential for the promotion of new RBC. Men lose only about 1 mg of iron each day but a woman loses about 20 mg during each normal menstrual period. A minimum of 5 to 15 mg of iron must be consumed in the daily food. Need for 1. Quadrillion is 1000000000000000=1015
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