Respiratory System

5. These blood vessels carry blood towards the heart. They have thin walls, due to low pressure.
6. These blood vessels carry blood away from the heart. They have thick muscular walls.
7. C _ _ _ _ _ dioxide is the 'waste' gas our body wants to remove.
8. The process when oxygen and carbon dioxide are replaced is known as gaseous _ _ _ _ _ _ _ _.
11. This is the 'useful' gas our body needs. It makes up around 21% of normal air.
12. The V _ _ _ _ box is where sound is produced. It is known as the larynx.

1. What 'D' is the process where gases move from a high concentration to a low concentration.
2. Is a part of the body which allows air to enter and exit the body.
3. What 'C' happens when the diaphragm flattens and creates more space.
4. Made from rings of cartilage, this splits into two bronchi. Also known as the 'windpipe'
9. There are about 600 million of these in the lungs. Is where gaseous exchange takes place.
10. We have two of these in the body. The main respiratory organ where oxygen and carbon dioxide are exchanged.