1 PowerPoint Lecture Outlines to accompany Hole’s Human Anatomy and Physiology Eleventh Edition Shier  Butler  Lewis Chapter 19 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Chapter 19 Respiratory System ventilation external respiration transport internal respiration cellular respiration Respiration is the process of exchanging gases between the atmosphere and body cells. Consists of the following events:

3 Organs of the Respiratory System

4

5 Upper Respiratory Tract

6 Mucous in Respiratory Tract Cilia move mucus and trapped particles from the nasal cavity to the pharynx

7 Sinuses Air-filled spaces in maxillary, frontal, ethmoid, and sphenoid bones

8 Pharynx

9 Larynx

10 Vocal Cords

11 Trachea

12 Tracheostomy Performed to allow air to bypass an obstruction within the larynx

13 Bronchial Tree

14 Alveoli

15 Diffusion Across Respiratory Membrane

16 Lungs

17 Transverse Section of Lungs

18 Breathing Mechanism Breathing or ventilation is the movement of air from outside the body into the bronchial tree and alveoli air movements of inspiration and expiration changes in the size of the thoracic cavity due to changes in pressure

19 Inspiration Moving the plunger of a syringe causes air to move in or out Air movements in and out of the lungs occur in much the same way

20 Lungs at Rest When lungs are at rest, the pressure on the inside of the lungs is equal to the pressure on the outside of the thorax

21 Inspiration Intra-alveolar pressure decreases to about 758mm Hg as the thoracic cavity enlarges Atmospheric pressure forces air into the airways

22 Inspiration Shape of thorax at end of normal inspiration Shape of thorax at end of maximal inspiration aided by contraction of sternocleidomastoid and pectoralis minor muscles

23 Major Events in Inspiration

24 Expiration due to elastic recoil of the lung tissues and abdominal organs

25 Maximal Expiration contraction of abdominal wall muscles contraction of posterior internal intercostal muscles

26 Major Events in Expiration

27 Respiratory Volumes and Capacities

28 Respiratory Volumes and Capacities

29 Alveolar Ventilation minute ventilation tidal volume multiplied by breathing rate amount of air that is moved into the respiratory passageways alveolar ventilation rate major factor affecting concentrations of oxygen and carbon dioxide in the alveoli volume of air that reaches alveoli tidal volume minus physiologic dead space then multiplied by breathing rate

30 Nonrespiratory Air Movements

31 Respiratory Center

32 Respiratory Center

33 Factors Affecting Breathing Decreased blood oxygen concentration stimulates peripheral chemoreceptors in the carotid and aortic bodies

34 Factors Affecting Breathing motor impulses travel from the respiratory center to the diaphragm and external intercostal muscles contraction of these muscles causes lungs to expand expansion stimulates stretch receptors in the lungs inhibitory impulses from receptors to respiratory center prevent overinflation of lungs

35 Factors Affecting Breathing

36 Alveoli gas exchanges between the air and blood occur within the alveoli alveolar pores allow air to pass from one alveolus to another

37 Respiratory Membrane consists of the walls of the alveolus and the capillary

38 Diffusion Through Respiratory Membrane Gases are exchanged between alveolar air and capillary blood because of differences in partial pressure

39 Oxygen Transport Most oxygen binds to hemoglobin to form oxyhemoglobin Oxyhemoglobin releases oxygen in the regions of body cells Much oxygen is still bound to hemoglobin in the venous blood

40 Oxygen Release Amount of oxygen released from oxyhemoglobin increases as partial pressure of carbon dioxide increases the blood pH decreases blood temperature increases

41 Carbon Dioxide Transport dissolved in plasma combined with hemoglobin in the form of bicarbonate ions

42 Chloride Shift bicarbonate ions diffuse out RBCs chloride ions from plasma diffuse into RBCs electrical balance is maintained

43 Carbon Dioxide in Lungs

44 Gases Transported in Blood

45 Life-Span Changes reflect accumulation of environmental influences reflect the effects of aging in other organ systems cilia less active mucous thickens swallowing, gagging, and coughing reflexes slow macrophages in lungs lose efficiency increased susceptibility to respiratory infections “barrel chest” may develop bronchial walls thin and collapse dead space increases

46 Clinical Application The Effects of Cigarette Smoking on the Respiratory System cilia disappear excess mucus produced lung congestion increases lung infections lining of bronchioles thicken bronchioles lose elasticity emphysema fifteen times more common lung cancer more common much damage repaired when smoking stops