2.44 structure of the thorax

1. Thorax is the biological word for chest
2. The chest is supported by a cage of bones called the ribs.
3. The ribs extend from the bone from the front called the sternum.
4. The ribs come out of the sternum and attach to the backbone, curving around.
5. There are two sheets of muscles between the ribs. These muscles are called the intercoastal muscles.
6. This is the meat tissue when we eat spare ribs.
7. Air enters through a tube beginning at the back of the throat and mouth and decending down into the lung area of the thorax. This tube is known as the trachea or windpipe.
8. The windpipe has cartilage rings that supports the tracheal tissue and stops it from collapsing.
9. The trachea divides into two. These two divisions are known as the bronchi. These are also supported by cartilage.
10. The right bronchi takes air into the right side of the lung whereas the left trachea takes air into the left side of the lung.
11. The brochis also divide into small tubes known as bronchioles. They are microscopic.
12. The larger bronchiles will also have cartilage support.
13. Due to many little bronchioles, the bronchis take up most of the tissue of the lung.
14. Bronchis end in dead end tubes, where the surface area has slightly increased. These dead end structures are known as alveolis.
15. The alveoli is where the gas exchange between air and blood take place in the lungs.
16. The two gases that are involved in gas exchange are carbon dioxide and oxygen.
17. On the surface surrounding the lung tissue is a membrane. This membrane is called the 'pleural membrane'.
18. The membrane that sits on the surface is known as the 'inner' pleural membrane.
19. Another membrane surrounds the pleural membrane known as the outer pleural membrane
20. The space between the two membranes contains the pleural fluid.
21. The outer pleural membrane is attatched to the ribcage.
22. The inner pleural membrane is attatched to the lung tissue.
23. Between the two membranes we have the pleural fluid which reduces friction as the lungs move during ventilation.