cancer

• genes in the nucleus tells cells when to divide and when to stop dividing
• sometimes mutations take place in genes which cause uncontrolled growth and division
• a tumor is a result of uncontrolled cell division and cell growth
• a benign tumour is a growth of abnormal cells that are contained within one area - usually within a membrane. The don't invade other parts of the body
• 3 things about benign tumours

  not cancerous

  grows until no more room

  if it causes pressure or damage to an organ is can be dangerous
• a malignant tumour is spread via the bloodstream or lymphatic system and can reach other organs. more uncontrolled cell division and growth can take place here = secondary tumor
• what is a malignant tumours

  cancerous
• cancer cells divide more rapidly and have a longer life span in comparison to normal cells
• malignant cells affect neighbouring tissues
• comes cancers are genetic = inherit certain genes which increase the likelyhood of getting cancer (breast or prostate)
• which 3 cancers are linked to lifestyle

  smoking = lung cancer

  alcohol = motuh and throat cancer

  uv light = skin cancer
• some

  substances in environment increase the risk of cancers like radon which is radioactive gas which increase risk of lung cancer

  radon realises ionising radiation which damages the DNA in our cells which leads to uncontrolled cell division which leads to cancer
• hair, skin and blood cells divide alot (naturally) howver in chemotherapy cannot divide between cancer cells and normal cells hence why these cells are affected by chemotherapy