The human body is a non-stop,24-hour blood manufacturing factory! And it carries on working, without any special effort from you, while you are busy in your office, or studying, sleeping, eating, laughing, dancing, playing a game of tennis... Production of red cells... Red cells have a life of only 120 days and are replenished by fresh cells throughout one's life. The new cells are formed in the bone marrow and transported through fine bones to the bloodstream. On a normal basis the rate of loss and reproduction is about 50 millilitres per 24 hours. A healthy body maintains the average count of 45,00,000 to 50,00,000 red cells per cubic millilitre (and haemoglobin content of 14.5 grams per 100 millilitre). and platelets... Like other components, platelets too are continuously produced by bone marrow, though sometimes one platelet generates another of its class. Platelets have an average life of 15 days and a count of 1,50,000 to 4,00,000 per cubic millilitre. and white cells... White cells too are produced in bone marrow and also in our liver and spleen. The count on an average is 6,000 to 8,000 per cubic millilitre and the life is only 6 to 7 hours! So a lot of activity is taking place all the time to see that stability is maintained in your body. In times of bacterial attack, these cells swell up to even greater numbers and then, after the infection is over, subside to normal count. and other components The protein components of plasma - albumin, globulin and fibrinogen, live for 15 days to one month and replacements are an ongoing process in the liver.