| How You Breathe | |
| Inhale (Breathing In) |
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| The job of your respiratory system is to carry gases between the outside air and your blood. |
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| Parts of the Respiratory System | ||
| Your respiratory system is at work whenever you smell, sing, talk, laugh, or breathe. Many parts of the respiratory system are coated with mucus. Mucus is a sticky, thick fluid that traps dust, germs, and other things that may be in the air. | ||
| Air enters through the nose or mouth. Sinuses warm and moisten the air. With its hairs and layer of mucus, the nose traps dust and germs. Air passes from the sinus to the back of the throat and into the larynx. The larynx contains the vocal cords. | ||
| The trachea is a tube that carries air from the larynx to the lungs. The trachea leads to two branches called bronchi that go into the lungs. In the lungs, these tubes branch into smaller and smaller tubes called bronchioles. Asthma is a disease in which these tubes may become narrowed. This prevents air from easily traveling through the lungs. | ||
| The bronchioles end in clusters of tiny thin-walled pouches or air sacs in the lungs. Air sacs are where oxygen enters the blood and carbon dioxide leaves the blood. Air sacs are also called alveoli. | ||
| The diaphragm is a dome-shaped muscle that forms the bottom of the chest area. When this muscle contracts it moves down and gets flatter. | ||
| 1. | What is the job of the air sacs? | |
| 2. | Draw a diagram of the respiratory system. Label and describe the function of all the parts. |
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| Exhale (Breathing Out) |
| Several muscles work together when you breathe. When you inhale, your diaphragm contracts and moves down, making more space in your chest. Your rib muscles may also pull your rib cage up and out, making still more space. Air quickly rushes into the lungs and takes up these new spaces. When your diaphragm and rib muscles relax, they push air out of the lungs. |
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| Vital lung capacity is the amount of air that a person can blow out after a deep breath. The vital lung capacity for an adult is often about 3 to 5 liters. |
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