Ch 16 Sect 1

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.

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.

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.

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.

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.

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