The respiratory system functions to transport gases to and from the circulatory system. It includes the nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles and alveoli. Oxygen is absorbed into the bloodstream in the alveoli and carried to cells while carbon dioxide is absorbed by red blood cells from tissues and released in the lungs. Breathing is controlled by the medulla oblongata and diaphragm to regulate lung volume and gas exchange.

1. Respiratory System Main function Transports GASES to and from the circulatory system

2. Parts of the Respiratory System

3. 1. Nasal Cavity

4. 2. Oral Cavity

5. 3. Pharynx Cavity at the back of the mouth Epiglottis is located in the pharynx

6. 4. Epiglottis Thin flexible cartilage structure Guards the entrance to the larynx Prevents food material from entering the trachea during swallowing

7. 5. Larynx Voice box (Glottis) Contains vocal cords

8. 6. Trachea Cartilage rings Windpipe

9. 7. Bronchi Made of up of smooth muscle & cartilage

10. 8. Bronchioles Same structure and function as bronchi, BUT smaller

11. 9. Alveoli Air sacs Tiny pouches surrounded by capillaries where gases are exchanged

13. Cilia and Mucus Air filtered by cilia Warmed & moistened by mucus Lines the nasal cavity, trachea, bronchi, bronchioles

14. Trachea Cilia will move debris up to trachea opening where the material will end up in the esophagus & will be swallowed.

15. Breathing

16. Inspiration/Inhalation Diaphragm CONTRACTS – “Down” position Chest expands and enlarges Ribs are PUSHED UP and OUT Thoracic cavity INCREASES More pressure outside than inside the lungs Allow air INTO the lungs

17. Expiration/Exhalation Diaphragm RELAXES - “Up” position Chest relaxes Ribs ARE IN and DOWN Thoracic cavity DECREASES , therefore pushes air OUT of the lungs More pressure inside the lungs than outside of the lungs Air is pushed

20. Animation of Breathing

21. Respiratory control

22. Medulla oblongata Located in the brain stem Controls respiratory rate Detects CO 2 levels in the blood

23. Diaphragm Respiratory muscle Regulates breathing Changes the VOLUME of the thoracic cavity

24. Gas Exchange

25. Gas exchange External gas exchange between the ATMOSPHERE and the BLOOD Internal gas exchange Between the BLOOD/CAPILLARY and the CELLS.

27. General Process of Gas Exchange

30. Gas Transport

31. Oxygen A small amount of oxygen in gas form dissolves in the BLOOD Most oxygen is carried by HEMOGLOBIN Lungs: Hemoglobin picks up oxygen Hb + O 2  HbO 2 (oxyhemoglobin) Cells: Hemoglobin drops off oxygen HbO 2  Hb + O 2

32. Carbon dioxide A small amount of carbon dioxide in gas form dissolves in the BLOOD (8%) 25% - carried by the HEMOGLOBIN Lungs: Hemoglobin drops off carbon dioxide HbCO 2  Hb + CO 2 Cells: Hemoglobin picks up carbon dioxide Hb + CO 2  HbCO 2

33. Carbon Dioxide 67% converted to BICARBONATE ions which dissolve in the PLASMA Cells - Carbon dioxide gets picked up CO 2 + H 2 O  H 2 CO 3  H + + HCO 3 - carbonic acid bicarbonate ion Lungs - Carbon dioxide gets dropped off H + + HCO 3 -  H 2 CO 3  CO 2 + H 2 O bicarbonate ion carbonic acid

34. CO 2 release to lungs

35. CO 2 pick up by RBC

36. Body and Breathing Activity

37. Bronchitis Inflammation of the air passages of the lungs Develops from a respiratory infection such as a cold Mucous lining become irritated/swollen Coughing is a reflex to clear secretions

38. Asthma Narrowing of the bronchi making breathing difficult Symptoms wheezing, difficulty breathing (particularly exhaling air), tightness in the chest Irritants Rapid changes in temperature or humidity, allergies, upper respiratory infections, exercise, stress, or smoke (cigarette)

40. Emphysema Damage to the tiny air sacs in your lungs (alveoli) Can cause you to feel short of breath Cigarette smoking is the major cause of emphysema, accounting for more than 80 percent of all cases

41. Carbon dioxide CO 2 produced by cellular respiration leaves the CELLS CO 2 enters the BLOOD VESSELS (veins) CO 2 enters the CAPILLARIES IN LUNGS CO 2 crosses the ALVEOLAR wall by DIFFUSION Exhale air

42. Oxygen Inhale O 2 O 2 crosses the ALVEOLAR wall by DIFFUSION O 2 enters the CAPILLARIES IN LUNGS O 2 enters the BLOOD VESSELS (arteries) O 2 travels to the CELLS to be used in cellular respiration

44. Transport of Gases in Blood Oxygen is mainly transported bound to hemoglobin though a small amount will dissolve in the blood Some carbon dioxide is transported bound to hemoglobin and some dissolves in plasma Most carbon dioxide molecules are transported in the form of bicarbonate ions Once in the lungs, the bicarbonate ions are converted back to carbon dioxide