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What is lung cancer?
Lung cancer is when the cells in your lung change and start to grow out of control. These cells increase to form a tumour. Cells from this tumour may spread to other parts of the body.
Almost 2,700 people are diagnosed with lung cancer each year in Ireland.
Sometimes cancer spreads to the lungs from somewhere else in your body, for example, from the breast or bowel. This is treated differently to cancer that starts in the lung (primary lung cancer). If you want to know about a cancer that has spread to the lung, please find that cancer type.
What are the lungs and what do they do?
The lungs are two organs found in your chest and form part of your respiratory system. This system is responsible for your breathing. Your right lung is slightly bigger than your left and has three areas called lobes. Your left lung has two lobes.
When you breathe in, air passes through your nose or mouth into your trachea (windpipe), which separates into two further tubes called bronchi. Each bronchus (left and right) connects to a lung. The bronchus divides even further into much smaller tubes called bronchioles. Air passes through these bronchioles and into tiny air sacs called alveoli.
In the alveoli, oxygen from inhaled air passes into your bloodstream and is sent around your body. The lungs are covered by a lining called the pleura, which has two layers. The pleural cavity also contains pleural fluid, which acts as a lubricant and allows the layers to slide effortlessly against each other during respiratory movements. The cavity between the two lungs is called the mediastinum. This cavity contains the heart, the oesophagus (food pipe), the trachea (windpipe), large blood vessels and lymph nodes. Oxygen is needed in every cell of your body for various activities. During these activities, the waste gas, carbon dioxide, is made. It passes back through the alveoli and leaves your body when you breathe out.
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