|MadSci Network: Medicine|
Hi Jennifer, I was recently asked a very similar question to yours so I'm going to copy some of that answer and add a little bit extra. The question is on the Mad Scientist Network and the ID number is 952846261.Me. I don't know how much you know about leukaemia and so I'll give a bit of background information. Leukaemia is a cancer of the bone marrow ( bm for short ). The bm makes all of your blood cells - the red blood cells carry oxygen around the body, the white blood cells fight infection and the platelets help the blood to clot. All the different types of cell in the blood come a single kind of cell called a stem cell which can either grow into 2 stem cells or it can mature into one of the different blood cells mentioned before. In leukaemia one type of blood cell turns cancerous and grows out of control - either too many cells grow too fast or the older cells don't die when they are supposed to. This means that the leukaemia cells take up all the space inside the bone and this stops the other types of cells from growing. If there aren't enough red blood cells you get anaemia, not enough white blood cells you get repeated infections, not enough platelets and your blood will not clot properly and you get bruising and easy bleeding - such as nosebleeds. Coagulation ( blood clotting ) relies on the platelets and coagulation factors - these are proteins usually made by the liver which float around in the blood in a dormant state. When you bleed these proteins are turned into their active forms and form a blob of jelly at the wound site where you are bleeding from. This blob of jelly traps platelets which change shape and consistency to give the clot substance, white cells which destroy bacteria and viruses trying to get in through the wound and cells called fibroblasts which carry out structural repairs to the wound.. To fight infections the bm produces different types of white blood cells. Some cells called neutrophils and monocytes work by 'eating' invading organisms - this is called phagocytosis, once the germ is inside the white cell the cell carries out some complicated chemical reactions to generate free radicals which act like acid and dissolve the germ. Other white cells called lymphocytes produce antibodies to identify invading organisms. A few cells from each group act as site managers by processing bits of the germ to help identification and by speeding up or slowing down the activity of the other immune cells. Red blood cells carry oxygen around the body, they can do this because they are full of a protein called haemoglobin. If the number of red cells being made by the bm falls too low you become anaemic - the organs and muscles in the body cannot get enough oxygen to work properly and so you get tired and short of breath very easily. People with leukaemia have bm problems for 3 general reasons - 1) The leukaemia cells stop platelets being made in the bm. 2) The treatment for leukaemia - chemotherapy ( drugs ) or radiotherapy ( radiation ) has side-effects. It can kill the stem cells which stops the different blood cells being made, it may stop the liver producing clotting factors or it may kill other cells such as hair follicle cells which is why people being treated for leukaemia can go bald. 3) The leukaemia cells spread to other organs ( just as other cancers can ) and if they invade the liver they can stop clotting factors being produced. If the leukaemia cells spread to the lymphatic system they can cause tumours in lymph glands such as the glands in your neck that swell up when you have a throat infection. These lymph glands are found throughout the body and if they grow too large they can squash other organs in the body which will stop those other organs working properly. In some leukaemias the leukaemic cells are very active and steal the bodys resources such as food and oxygen for their own growth, this activity also produces a lot of waste products which cannot also be removed fast enough and poison the body. The above are some of the effects of leukaemia on the body, unfortunately I cannot go into much more detail because things get rather complicated such as showing how hormones produced in one part of the body can be affected by the leukaemia disease process and cause unexpected problems in a part of the body away from the bm. Information about leukaemia can be found through the following sites but there are a lot more sites on the net - http://www.children-cancer.com/ http://www.choa.org/hemonc/default.shtml Hope this helps, NIGE
Try the links in the MadSci Library for more information on Medicine.