| What happens when a cell becomes cancerous? | When a cell becomes cancerous, it begins to grow and divide uncontrollably. New cells are produced – even if the body does not need them
- A group of cancerous cells produces a growth called a tumour.
- Cancer cells are undifferentiated – they do not carry out their normal function |
| 2 Types of Tumours | Benign-
(1)Grows slowly
(2)usually within a membrane so easy to remove
(3)doesnt invade other parts of the body
Melignant-
(1)Grows quickly
(2)not within a membrane
(3)invades neighbouring tissues spreads to other parts of body
(4)undergoes metastasis (forming of secondary tumors) |
| Describe how Secondary Tumours form | 1) Tumour secretes chemicals
2) The chemicals stimulate the blood vessels to grow (the blood vessels grows around the tumour)
3) Cancer cells detach from the tumour and are transported in the blood
4) A malignant cell squeezes through a blood capillary wall
5) The cell divides - a secondary tumour starts to grow |
| State 3 Life Style Factors that may cause Cancer | 1) viruses linked with cancer, such as the human papilloma virus (HPV), being spread from person to person through sexual intercourse
2) the chemical carcinogens in cigarette smoke increasing the risk of lung cancer
3) alcohol intake is linked with certain cancers
4) exposure to ultraviolet radiation, part of which is ionising, during sunbathing or outdoor activities, leading to the development of skin cancers
5) diet, including fat and salt intake, increases the risk of cancer |
| State an Industrial and environmental factor at work that may cause Cancer | 1) exposure to ionising radiation increases the risk factor
2) exposure to carcinogens |
| What are Carcinogens? | Chemical and other agents that can cause cancer
- Carcinogens cause cancer by damaging DNA.
- Carcinogens cause mutations to occur. A single mutation will not cause cancer – several are required. For this reason, we are more likely to develop cancer as we get older |
