Cancer is a large group of disorders with different symptoms Almost all cancers have the same cause: cells multiplying uncontrollably The bad genes at the start of the problem may be inherited, caused by known carcinogens or just by ageing. A cancerous cell divides to form two cells that contain damaged genetic material . If these are left untreated the cancerous cell will multiply uncontrollably. Once you have cancer in one place it can travel to other places in your body.
First carcinogens continually bombard cells and many eventually affect genes on the chromosomes. Often new damage to the oncogenes is limited and soon repaired. Second damage to oncogenes and repair continue, but with time or higher than normal exposure to carcinogens, some of the oncogenes suffer permanent harm. Eventually a number of oncogenes are permanetly altered. Key cell functions are irreparably affected and the cell tips over into cancerous mode. Carcinogens -A substance capable of causing cancer in living tissue Oncogenes- A gene that in certain circumstances transforms a cell into a tumor cell.
Cancer is a growth that damages surrounding tissues and organs. Non cancerous cells divide and replace at a controlled rate. A cancerous tumor is a mass of abnormal cell that divide extremely quickly and don’t carry out the normal functions of their tissue. These cells are often irregular in size and shape. As these cells divide and multiply a tumor can gradually enlarge.
It takes just one cell to undergo cancerous changes for a tumor to form. The cell divides into two cells which do the same and so on. the total number of cancerous cells double every division. After 25-30 divisions there are around a billion cells which then you can see a tumor forming.
Cancer can be spread by lymph and by blood If the tumor is near a lymph vessel then eventually the cancer cells will go through the vessel and reach the lymph node. Once it reaches the lymph node it will for a tumor. If a cancer cell gets into the blood the cell will travel all over to places that are reached by blood vessels. The cancer cells will slowly go out of the vessels and form a tumor.
Bone Cancer Lung Cancer Brain Cancer Cancer in children Breast Cancer Skin Cancer Anal Cancer Testicular Cancer Eye Cancer Bladder Cancer Leukemia Intestinal Cancer
Breast Cancer is a malignant tumor that starts in the cells of the breast. The disease usually occurs in women but sometimes it may occur in men. The female breast is made up of lobules, ducts, and stroma Most breast cancer start in the cell that lines the ducts
leukemia starts in the soft part of the bone (the bone marrow) so it spreads quickly to the blood and once that happens it can spread to other parts of your body, such as the lymph nodes, spleen, liver, as well as the central part of your nervous system, and other organs. Children and adults can get leukemia witch is a complex daises with many types and subtypes. Bone marrow is the soft spongy part of the part of the bone and all these different blood cells are made in the marrow
Anal cancer is a rare disease that attacks the anus. The Anus is the bodies opening to the lower intestine. The anal and its surrounding are made up of several different types of cells were tumors can begin to develop. Not all anal tumors develop in to cancer
www.cancer.org The Human Body BookCopyright 2007 Dorling Kindersley Limited