The respiratory system consists of the airways, lungs, ribs, diaphragm and intercostal muscles. The airways include the nose, mouth, trachea, two bronchi, bronchioles and alveoli. Gas exchange takes place in the alveoli. Oxygen diffuses from the alveoli into the bloodstream and carbon dioxide and water vapour diffuse from the bloodstream into the alveoli. Alveoli are adapted for gas exchange: they are numerous, have a large surface area, are one cell thick, are surrounded by a dense network of capillaries and are moist. The diaphragm and intercostal muscles contract during inhalation and relax during exhalation. Exhaled air contains carbon dioxide and water vapour. Exhaled air contains more carbon dioxide than inhaled air. Exercise increases the rate of breathing. The respiratory system interacts with the circulatory system to bring oxygen to the body and to remove carbon dioxide. Asthma is a condition that affects the respiratory system. It is caused by inherited and environmental factors. Smoking is a lifestyle factor that affects the respiratory system.
Questions and Exercises K C
Key Concepts Rewrite the following sentences in your copybook and fill in the blanks. 1. The nose contains _____________ and _____________ to trap dirt. 2. The larynx contains two _____________ _____________ which can produce sound.
3. The _____________ contains rings of cartilage. 4. Two _____________ carry air into the lungs. 5. The smallest air tubes are called _____________. 6. The air sacs at the end of these tubes are called _____________. 7. Muscles called the _____________ and _____________ _____________ are involved in breathing.
8. _____________ _____________ takes place in the alveoli. 9. The alveoli are surrounded by _____________. 10. Oxygen is carried in the blood by the _____________ _____________ __________. 11. Aerobic respiration produces _____________ _____________ and _____________ as waste products.
12. Carbon dioxide is transported in the _____________. 13. Exhaled air contains _____________ carbon dioxide than inhaled air.
