Science: The Respiratory System
How the body takes in oxygen and removes carbon dioxide
Science: The Respiratory System
How the body takes in oxygen and removes carbon dioxide
Biology - Grade 6-8
- 1
What is the main job of the respiratory system in the human body?
Think about the gases you breathe in and breathe out.
The main job of the respiratory system is to bring oxygen into the body and remove carbon dioxide from the body. - 2
List the path air follows as it enters the body through the nose or mouth and travels to the lungs.
Air enters through the nose or mouth, moves through the pharynx, passes the larynx, goes down the trachea, enters the bronchi, and then travels into smaller bronchioles in the lungs. - 3
What is the function of the trachea?
It is sometimes called the windpipe.
The trachea is the tube that carries air from the larynx toward the bronchi and lungs. - 4
Explain what happens in the alveoli.
In the alveoli, oxygen moves from the air into the blood, and carbon dioxide moves from the blood into the alveoli to be breathed out. - 5
Why are alveoli well suited for gas exchange?
Think about their structure and how many there are.
Alveoli are well suited for gas exchange because they have thin walls and a large surface area, which helps oxygen and carbon dioxide move easily between the air and the blood. - 6
Describe the role of the diaphragm in breathing.
The diaphragm is a muscle below the lungs that helps breathing. When it contracts, it moves downward and helps air enter the lungs. When it relaxes, it moves upward and helps air leave the lungs. - 7
What is the difference between inhaling and exhaling?
One process brings oxygen in, and the other removes carbon dioxide.
Inhaling means breathing air into the lungs, while exhaling means breathing air out of the lungs. - 8
How do the respiratory system and circulatory system work together?
The respiratory system brings oxygen into the lungs and removes carbon dioxide. The circulatory system carries oxygen from the lungs to body cells and brings carbon dioxide back to the lungs to be exhaled. - 9
Name two ways the nose helps prepare air before it reaches the lungs.
Think about cleaning and conditioning the air.
The nose helps by filtering dust and other particles from the air, and it also warms and moistens the air before it reaches the lungs. - 10
How can smoking damage the respiratory system?
Smoking can damage the respiratory system by irritating and harming the airways and alveoli, reducing lung function, and making it harder for the body to exchange gases effectively. - 11
A student says that the lungs are muscles that push air in and out. Explain why this statement is incorrect.
Think about which body parts actually contract during breathing.
This statement is incorrect because the lungs are not muscles that push air by themselves. Breathing is mainly caused by the diaphragm and other muscles changing the space in the chest so air moves in and out of the lungs. - 12
Why does your breathing rate usually increase during exercise?
Your breathing rate usually increases during exercise because your muscles need more oxygen and produce more carbon dioxide, so your body breathes faster to exchange these gases more quickly.