1. INTERNAL AND EXTERNAL

2. CELLULAR METABOLISM ANAEROBIC GLYCOLYSIS AEROBIC OXIDATIVE METABOLISM IN THE MITOCHONDRIA

3. Ventilation or breathing: air moved in and out of lungs Oxygen and Carbon Dioxide exchange in the lungs Oxygen and Carbon Dioxide transported by blood to and from tissues Exchange of Oxygen and Carbon Dioxide between tissue and blood

4. HEART TISSUE CELL O 2 + FOOD CO 2 + H 2 O + ATP LUNGS ATMOSPHERE PULMONARY CIRULATION SYSTEMIC CIRCULATION

5. Nasal Passages Mouth Pharynx Larynx Trachea Bronchi Alveoli Lung

6. Small, thin walled, inflatable sacs at end of bronchioles Surrounded by jacket of pulmonary capillaries Provide thin barrier and enormous surface area for gas exchange by diffusion Type II secrete surfactant

8. The Mechanics of Breathing

9. Atmospheric pressure: 760 mm Hg Intra-alveolar pressure: 760 mm Hg Intrapleural pressure: 756 mm Hg

10. Mercury Hg VACUUM WEIGHT OF COLUMN OF AIR = FORCE FORCE/AREA = PRESSURE Sea Level 760 mm

11. 760 MM Hg 756 mmHg Lungs Intrapleural pressure Airways Atmosphere Pleural Sac Thoracic Wall

12. Thoracic cavity larger than lungs Transmural (Across Lung Wall) pressure gradient holds thoracic wall and lungs in close apposition This pressure gradient is balanced by the elastic forces in the alveoli producing equilibrium

13. 760 MM Hg 756 mmHg Lungs Intrapleural pressure Airways Atmosphere Pleural Sac Thoracic Wall

14. P 1 V 1 = P 2 V 2 If Volume increases, Pressure must decrease As lungs expand, pressure inside falls

15. Elevation of ribs expands lungs Lowering of diaphragm by contraction also expands lungs Expansion of lungs causes pressure inside to drop below atmospheric pressure Air rushes in to fill the expanded lungs

16. 760 mm Hg 754 mmHg Lungs Intrapleural pressure Airways Atmosphere Pleural Sac Thoracic Wall 759mm Hg

17. Return of ribs to rest position causes diminishing of lung volume Return of diaphragm to rest position also causes diminishing of lung volume Diminishing of lung volume causes pressure in lung to raise to a higher value than atmospheric pressure Air flows out of the lungs

18. 760 mm Hg 756 mmHg Lungs Intrapleural pressure Airways Atmosphere Pleural Sac Thoracic Wall 761 mm Hg

19. Sternocleidomastoid Scalenus External Intercostals Diaphragm

20. Internal intercostals Abdominals

21. Flow of air depends on the pressure gradient (atmospheric, P a, and intra-alveolar, P i ) and the airway resistance, R F = (P a - P i )/R Resistance depends primarily on the radius of the conducting airways Parasympathetic stimulation constricts, while sympathetic dilates

22. Colds Asthma: Constriction of small airways, excess mucus, and histamine-induced edema Bronchitis:Long term inflamitory response causing thickened walls and overproduction of mucous Emphysema: Collapse of smaller airways and breakdown of alveolar walls Alveolar surface tension

23. Tidal Volume (TV): 500 ml Inspiratory reserve volume (IRV): 3 liters Inspiratory capacity (IC): 3.5 liters Expiratory reserve volume (ERV): 1 liter Residual volume (RV): 1.2 liters Functional Residual Capacity (FRC): 2.2 l Vital Capacity (VC): 4.5 liters Total Lung Capacity (TLC): 5.7 liters

25. IC = IRV + TV FRC = ERV + RV VC = IRV + TV + ERV TLC = VC + RV