1. Health 8
Chapter 15
Lesson 4

2. Lesson 4
DID YOU KNOW? The carbon dioxide you exhale as a waste product is absorbed by plants and converted back to oxygen?
I. THE NEED FOR AIR
A. Air contains oxygen, a gas the body needs to maintain life.
B. Breathing - inhaling and exhaling - is carried out by the respiratory system.

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C. The system consists of organs that provide the body with a continuous supply of oxygen and rid the body of carbon dioxide.

4. Lesson 4 D. Parts of the respiratory system include the following:
1. Air enters the body through the nose and mouth. Both the nose and the mouth are lined with mucous membranes. Fine hairs called cilia trap dirt that is breathed in.

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2. The throat contain 2 passageways - one for food and one for air.
3. The epiglottis is a flap of tissue that closes over trachea when you swallow.

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4. The larynx is the upper part of the respiratory system, which contains the vocal cords.
5. The trachea is a windpipe that directs air into the lungs.
6. The bronchi are the passages through which air enters the lungs.

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7. In the lungs, oxygen is transferred to the blood, and carbon dioxide is removed from the blood.
8. The diaphragm is a dome-shaped muscle that separates the lungs from the abdomen.
Where would you expect to find pure air to breathe?

8. Lesson 4 II. HOW THE RESPIRATORY SYSTEM WORKS
A. The respiratory system has two important job.
1. It supplies oxygen to the blood - oxygen that is then carried to all the cells of the body.
2. It removes carbon dioxide from the blood and releases it outside the body.

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10. Lessn 4 B. When you inhale, you bring air into your body from outside.
C. When you exhale, you release air to the outside.
D. In this process, oxygen is exchanged with carbon dioxide inside your lungs. This continual exchange of gases helps maintain a constant supply of oxygen in your cells.

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1. When you inhale, your diaphragm contracts and moves down. Your ribs move out and up, increasing the size of your chest cavity. Ai moves through your nose and mouth and into your lungs.

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2. When you exhale, your diaphragm relaxes and moves up into your chest cavity and forces air out of your lungs.
E. The air that you exhale contains more carbon dioxide and less oxygen than the air that you inhale. Carbon dioxide - containing blood is pumped from the heart to the lungs through the pulmonary arteries and capillaries.

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F. Carbon dioxide passes from the blood into bronchioles, which are smaller bronchial tubes, and then into alveoli - microscopic air sacs in the lungs. Here, carbon dioxide is exchanged with oxygen. Oxygen passes from from the alveoli to capillaries and into the blood.

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Why do you need oxygen.

15. Lesson 4 III. PROBLEMS OF THE RESPIRATORY SYSTEM
A. Problems of the respiratory system include the following:
1. Influenza and colds are caused by viruses. The symptoms include coughing, runny nose, aches and fever.

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2. Bronchitis is swelling of the bronchi - the lungs' air passages - due to infection. It causes coughing, fever, and chest tightness.
3. Allergies are immune responses to foreign substances in the environment. They can cause sneezing, itchy eyes, runny nose and hives.

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4. Asthma is an inflammatory disease that causes the bronchi t become blocked or narrowed. its symptoms are wheezing, shortness of breath, and coughing.
5. Pneumonia is a lung infection caused by viruses or bacteria. It can lead to fever, chest pain, and breathing difficulties.

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6. Emphysema is a disease in which the alveoli are damaged or destroyed. Strongly linked to smoking, it causes serious breathing difficulties.

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7. Tuberculosis is a bacterial lung infection that causes a dry cough in the early stages and chest pain later on.
8. Lung cancer is a disease in which tissues of the lung are destroyed by the growth of a tumor. The cause in most cases in smoking or secondhand smoke.

20. Lesson 4 IV. CARE OF THE RESPIRATORY SYSTEM
A. You can keep your respiratory system working at its peak b following some common sense practice.
1. Stay active
2. Avoid smoking and secondhand smoke.
3. Avoid polluted air

21. Lesson 4 4. Use a mask in conditions that warrant one.
5. Reduce your risk of respiratory infection.