1. Respiratory System
Science 7

2. The Respiratory System’s function is to transport gases (oxygen and carbon dioxide) to and from the circulatory system.

3. Respiration is the process of obtaining and using oxygen from the air and getting rid of carbon dioxide and water.
Respiration is made up of 2 parts:
A. Breathing – inhaling and exhaling
B. Cellular Respiration – Chemical reactions that release energy from food

4. First Stop – The NOSE
The nose is the primary passageway into and out of the respiratory system.
(Yes – air can also be inhaled and exhaled through the mouth but most of the time you use your nose.)

5. Second Stop – The Pharynx
The pharynx (also known as the throat) has two branches – one carries air to the lungs (larynx), the other carries food to the stomach (esophagus).
What do you think stops the food from going to the lungs???

6. The Larynx
Tilt your head back and run your finger gently over your throat. You will feel ridges. This is your larynx.
The larynx (also known as the voice box) contains your vocal cords. When air passes over your vocal cords they vibrate and make noise.

7. Next Stop – The Trachea
The trachea (also known as the windpipe) is a large tube that air travels down to get from the larynx to the lungs.
The walls of the trachea are lined with rings of cartilage to hold it open.
The trachea is lined with cilia and mucus. The cilia (small hair like structures) move the mucus to the pharynx.

8. The Bronchi
The trachea branches into 2 tubes called Bronchi. Each bronchi lead to each of your 2 lungs.

9. The Lungs
The lungs are the main organ in your respiratory system. You have two large sponge-like lungs.

10. Inside the lungs, the bronchus split into smaller branches to form thousands of tiny sacs called alveoli (alveolus).
The capillaries surround the alveolus and absorb the oxygen which is then carried into the circulatory system.

11. So, how do you breathe?
Your lungs do not contain muscles that push the air in and out.
Breathing is actually done by the ribs and the diaphragm.

12. The diaphragm is a dome-shaped muscle at the bottom of your chest.
It pulls down when you inhale to help pull air into the lungs, and it pushes up when you exhale to help push air out of the lungs.

13. Disorders that can occur in your respiratory system:
Asthma – is when a person has difficulty breathing because irritants around the bronchioles to constrict and secrete large amounts of mucus.
Bronchitis – is something that can develop when something irritates the bronchioles.
Pneumonia – is caused by a bacteria or virus that grows inside the bronchioles and alveoli and cause them to become inflamed and fill with fluid. If there is too much fluid, a person could suffocate.

14. Smoking is the leading cause of cardiovascular and lung diseases.
Lung Cancer and Emphysema are the top 2.

15. Lungs infected with emphysema. X-ray of lungs infected with emphysema.
Emphysema is when the lung tissue is eroding away and the person has trouble getting the oxygen they need.
Lungs infected with emphysema.
X-ray of lungs infected with emphysema.