1. Ch 16 Sect 1

2. Functions of the Respiratory System
Breathing is the movement of air into and out of the lungs.
Takes in O₂ and eliminates CO₂
Cellular Respiration requires O₂
During cellular respiration, oxygen and sugars react and release energy.
Respiratory system removes CO₂ and other waste gases from the body.

4. Organs of the Respiratory System
Air enters the mouth and the nose (warms & moistens). Hair and mucus trap dust and dirt.
Cilia help prevent harmful particles from getting into the respiratory system.
Pharynx (throat) – a tubelike passageway at the top of the throat that receives air, food, and liquids from the nose or mouth.
Epiglottis – flap of tissue at the lower end of the pharynx. Keeps food & liquids from entering the respiratory system.

5. Organs of the Respiratory System
Larynx (voice box) – triangle shaped area that receives air from the pharynx and sends it to the trachea. Vocal cords are located in the layrnx.
Trachea – a tube that is held open by C-shaped rings of cartilage. Receives air from the larynx and sends it to the bronchi.

7. Bronchi, Lungs, & Alveoli
Bronchi –narrow tubes that lead into the lungs.
Bronchi branch into smaller tubes called bronchioles (located inside the lungs).
Lungs- main organs of the respiratory system.
Alveoli- air sacs located at the end of the bronchioles. (Gas exchange occurs here). Surrounded by capillaries.

9. Breathing and Air Pressure
High levels of CO₂ build up in the blood, the nervous system signals your body to breathe out.
Diaphragm – a large muscle below the lungs that contracts and relaxes and moves air in and out of the lungs.
Inhalation- diaphragm contracts, air moves in
Exhalation – diaphragm relaxes, air moves out.

10. Respiratory Health Irritants can cause respiratory illnesses:
1. Colds, flu
2. Bronchitis
3. Pneumonia
4. Asthma
5. Emphysema
6. Lung Cancer