2. The Respiratory System

3. I. Overview  Consists of 6 major organs: nose, pharynx, larynx, trachea, bronchial tubes, and lungs  Function together to perform breathing  Works with circulatory system to deliver oxygen to all cells of the body and remove carbon dioxide (CO 2 )

4. II. Respiration  Divided into 3 parts: ventilation, external respiration and internal respiration 1. Ventilation- flow of air between the outside environment and lungs a.Inhalation- flow of air into the lungs- brings in fresh O 2 b.Exhalation- flow of air out of the lungs – removes CO 2

5. 2. External Respiration a. Is the exchange of O 2 and CO 2 that takes place in the lungs b. Gases diffuse in opposite directions between the air sacs of the lungs and bloodstream (O 2 enters bloodstream from air sacs, CO 2 does the opposite)

6. 3. Internal Respiration a. Aka tissue breathing b. Process of O 2 and CO 2 exchange at the cellular level for metabolism c. O 2 leaves blood to go the tissues d. CO 2 becomes the by-product of metabolism

7. III. Nose  The process of ventilation begins with the nose  Air enters the nasal cavity through the nares (2 openings)  Nose is divided in the middle by the nasal septum  The palate (roof of mouth) separates the nasal cavity from the mouth

8.  Nasal cavity lined with mucous membrane that secretes mucous- which cleanses air by trapping dust and bacteria and moisturizes inhaled air  Cilia- small hairs that line the opening to the nose that serve as filters  Paranasal sinuses- air-filled cavities located within the facial bones – act as an echo chamber

9. IV. Pharynx  Next air enters the pharynx (throat)  Consists of 3 parts: nasopharynx, oropharynx and laryngopharynx  Nasopharynx, contains the adenoids, or pharyngeal tonsils  Oropharynx, contains palatine and lingual tonsils  The eustachian or auditory tube is located in the nasopharynx and opens to equalize air pressure every time we swallow

10. V. Larynx  Aka the voice box  Muscular structure between the pharynx and trachea that contains the vocal cords  Sound is produced by vibration as air passes through the glottis – opening between the 2 vocal cords  The epiglottis sits above the glottis and provides protection against food and liquid being inhaled into the lungs

11.  The walls of the larynx are made up of several cartilage plates, one of them the thyroid cartilage that forms the Adam’s apple. –Usually larger in males than females, helping to produce the deep voice in males

12. VI. Trachea  Aka the windpipe  Passageway for air that goes from the pharynx and larynx down to the main bronchi  Lined with mucous and cilia to assist in cleansing, warming and moisturizing air as it goes to the lungs