Understanding the Human Respiratory System: Gas Exchange and Transport

1. Section 3 The Respiratory System Chapter 46 Objectives • Differentiateexternal respiration from internal respiration. • Tracethe path of air from the atmosphere to the bloodstream. • Describehow gases are exchanged in the lungs and transported in the bloodstream.

2. Section 3 The Respiratory System Chapter 46 Respiration • The function of the respiratory system is to exchange gases with the cardiovascular system. • The respiratory system involves both external respiration and internal respiration. • External respiration is the exchange of gases between the atmosphere and the blood. • Internal respiration is the exchange of gases between the blood and the cells of the body.

3. Section 3 The Respiratory System Chapter 46 The Human Respiratory System

4. Section 3 The Respiratory System Chapter 46 Parts of the Human Respiratory System Click below to watch the Visual Concept. Visual Concept

5. Section 3 The Respiratory System Chapter 46 The Lungs • The lungs are the central organs of the respiratory system in which gases are exchanged. • The lungs are located inside thethoracic cavity,which is bound by the rib cage and the diaphragm.

6. Section 3 The Respiratory System Chapter 46 The Lungs, continued • The Path of Air • External respiration begins at the mouth and at the nose. • Air is filtered & moved into the tube at the back of the mouth called the pharynx (aka throat).

7. Section 3 The Respiratory System Chapter 46 The Lungs, continued • The Path of Air, continued • Air then moves past the from the epiglottis into a cartilaginous tube, called the trachea. • The epiglottis is a flap of cartilage that hangs at the entrance of the larynx and directs food and air to the correct places.

8. Section 3 The Respiratory System Chapter 46 The Lungs, continued • The Path of Air, continued • At the end of the trachea, the air moves into the two bronchi and into the lungs. • The air then moves into smaller tubes called the bronchioles. • Air then moves to the alveoli where gas exchange takes place.

9. Section 3 The Respiratory System Chapter 46 Gas Exchange and Transport • Gas Exchange in the Lungs • Alveoli are surrounded by webs of capillaries. The air passes from the alveoli to the capillaries via diffusion to be transported throughout the body. • At the same time, carbon dioxide passes from the capillaries to the alveoli via diffusion to be exhaled as waste.

10. Section 3 The Respiratory System Chapter 46 Gas Exchange in the Lungs

11. Section 3 The Respiratory System Chapter 46 Gas Exchange and Transport, continued • Transport of Oxygen • Most of the oxygen absorbed into the blood combines with hemoglobin, which distributes the blood to cells.

12. Section 3 The Respiratory System Chapter 46 Hemoglobin and the Transport of Oxygen Click below to watch the Visual Concept. Visual Concept

13. Section 3 The Respiratory System Chapter 46 Blood and the Transport of Carbon Dioxide Click below to watch the Visual Concept. Visual Concept

14. Section 3 The Respiratory System Chapter 46 Mechanism of Breathing • Breathing is the process of moving air into and out of the lungs. • Inspiration is the process of taking air into the lungs. • When a deep breath is taken, the chest and ribs expand.

15. Section 3 The Respiratory System Chapter 46 Mechanism of Breathing, continued • Expiration is the process of releasing air from the lungs. When this happens, the diaphragm and rib muscles relax, which forces the lungs to deflate.

16. Section 3 The Respiratory System Chapter 46 Inhalation and Exhalation