Year 9 Science Quiz: The Respiratory System

Instructions

Answer the following questions about the respiratory system. Each question requires a short answer. Good luck!

Describe the main function of the respiratory system in the human body.
Explain the process of gas exchange that occurs in the alveoli.
Identify four major components of the respiratory system and briefly describe the role of each component.
What are the differences between inhalation and exhalation in terms of muscle action and air pressure?
Discuss the impact of smoking on the respiratory system and mention at least four diseases associated with it.

The main function of the respiratory system is to facilitate the exchange of oxygen and carbon dioxide between the body and the environment.
Gas exchange in the alveoli occurs when oxygen from the inhaled air passes through the alveolar walls into the blood, while carbon dioxide from the blood passes into the alveoli to be exhaled.
- Nose/Mouth: Air enters the respiratory system here; filters, warms, and moistens the air.
- Trachea: The windpipe that channels air to the lungs; contains cilia and mucus to trap substances.
- Lungs: Organs where gas exchange occurs; they contain alveoli where oxygen and carbon dioxide swap.
- Diaphragm: A muscle that contracts and relaxes to aid in breathing; it helps to expand and compress the chest cavity.
Inhalation involves the contraction of the diaphragm and intercostal muscles, reducing pressure in the thoracic cavity and allowing air to flow in. Exhalation involves the relaxation of these muscles, increasing pressure and pushing air out.
Smoking impacts the respiratory system by damaging the airways and alveoli, leading to diseases such as lung cancer, chronic bronchitis, emphysema, and asthma. Smoking also decreases lung function and can lead to respiratory infections.