1. 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Human Biology Sylvia S. Mader Michael Windelspecht Chapter 9 Respiratory System Lecture Outline Part 2

2. 2 The bronchial tree The bronchial tree starts with 2 main _________ that lead from the trachea into the lungs. The bronchi continue to branch until they are small _____________ about 1 mm in diameter with thinner walls. Bronchioles eventually lead to elongated sacs called ________. 9.3 The Lower Respiratory Tract

3. 3 The lungs The secondary bronchi, bronchioles, and alveoli make up the lungs. The right lung has 3 lobes while the left lung has 2 lobes. Each lobe is divided into lobules. Each lung is enclosed by membranes called pleura. 9.3 The Lower Respiratory Tract

4. 4 The alveoli There are 300 million alveoli in the lungs that greatly increase _____________. Alveoli are enveloped by blood capillaries. The alveoli and capillaries are __________ of epithelium to allow exchange of gases. Alveoli are lined with ____________ that act as a film to keep alveoli open. 9.3 The Lower Respiratory Tract

5. 5 The alveoli Figure 9.6 Pulmonary circulation to and from the lungs. 9.3 The Lower Respiratory Tract Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. alveoli capillary network lobule bronchiole blood flow pulmonary vein pulmonary artery Pulmonary arteriole contains much CO 2, little O 2. Pulmonary venule contains much O 2, little CO 2

6. 6 2 phases of breathing/ventilation 1. Inspiration – an _______ process of inhalation that brings air into the lungs 2. Expiration – a typically _________ process of exhalation that expels air from the lungs 9.4 Mechanism of Breathing

7. 7 Inspiration The __________ and ___________ muscles contract. The diaphragm ________ and the rib cage moves upward and outward. Volume of the thoracic cavity and lungs increase. The air pressure within the lungs ___________. Air flows into the lungs. 9.4 Mechanism of Breathing

8. 8 Inspiration Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 9.7a The thoracic cavity during inspiration. 9.4 Mechanism of Breathing a. Inspiration Rib cage moves up and out. lungs lung rib cage Diaphragm contracts and moves down. When Pressure in lungs decreases, air comes rushing in. trachea air in External intercostal muscles pull the ribs outward.

9. 9 Expiration The diaphragm and intercostal muscles ______. The diaphragm moves ________ and becomes ______-shaped. The rib cage moves downward and inward. Volume of the thoracic cavity and lungs ________. The air pressure within the lungs _________. Air flows out of the lungs. 9.4 Mechanism of Breathing

10. 10 Expiration Figure 9.7b The thoracic cavity during expiration. 9.4 Mechanism of Breathing Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b. Expiration Internal intercostal muscles pull the ribs inward during forced expiration. Rib cage moves down and in. Diaphragm relaxes and moves up. When pressure in lungs increases, air is pushed out. air out

11. 11 Different volumes of air during breathing ___________ – the small amount of air that usually moves in and out with each breath ___________ – the maximum volume of air that can be moved in plus the maximum amount that can be moved out during one breath Inspiratory and expiratory ______________ – the increased volume of air moving in or out of the body _________ volume – the air remaining in the lungs after exhalation 9.4 Mechanism of Breathing

12. 12 Air pressure and volume Figure 9.8 The relationship between air pressure and volume. 9.4 Mechanism of Breathing Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 2 3 Sides of container move inward air pressure increases air moves out of container b. 1 2 3 sides of container move outward air pressure decreases a. air moves Into container

13. 13 Visualizing the vital capacity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 5,800 4,800 3,600 2,900 2,400 1,200 0 Average Lung Volume (ml) maximum inspiration maximum expiration inspiratory reserve volume tidal volume expiratory reserve volume residual volume residual volume vital capacity total Lung capacity (right): © Burger/Photo Researchers, Inc. Figure 9.9 Measuring the vital capacity of the lungs. 9.4 Mechanism of Breathing