Outline

1. Respiratory Systems

2. Outline • Gas Exchange Surfaces • Water Environments • Gills • Land Environments • Lungs • Human Respiratory System • Inspiration versus Expiration • Respiration and Health • Respiratory Disorders

3. Gas Exchange Surfaces • Respiration: • The events associated with gas exchange between the cells and the external environment • Consists of • Ventilation • External Respiration • Internal Respiration

4. Gas Exchange Surfaces • For diffusion to be effective, gas-exchange regions must be: • Moist • Thin • Relatively large • Effectiveness of diffusion is enhanced by vascularization • Delivery to cells is promoted by respiratory pigments (like hemoglobin)

5. Water Environments • Gasses of air can dissolve in water • However • When saturated, water contains small fraction of the O2 in same volume of air, and • Water is much more viscous than air • Aquatic animals expend more energy to breathe than do terrestrial animals

6. Gas Exchange • Hydras and planarians • Small animals with large surface area • Most of their cells exchange gases directly with the environment • Larger aquatic animals • Often have gills • Finely divided vascularized outgrowths of inner body surface • Gills of bony fishes • Outward extensions of pharynx • Ventilation is brought about by combined action of the mouth and gill covers (operculum) • Countercurrent Exchange

7. Animal Shapes and Gas Exchange

8. Anatomy of Gills in Bony Fishes

9. Land Environments:Tracheae • Insects and other terrestrial arthropods • A respiratory system consists of branched tracheae • Oxygen enters tracheae at spiracles • Tracheae branch until end in tracheoles that are in direct contact with body cells

10. Tracheae of Insects

11. Land Environments:Lungs of Vertebrates • Terrestrial vertebrates have evolved lungs • Vascular outgrowths from lower pharyngeal region • Lungs of amphibians • Possess a short tracheae which divides into two bronchi that open into lungs • Many also breathe to some extent through skin • Reptiles • Inner lining of lungs is more finely divided in reptiles than in amphibians • Lungs of birds and mammals are elaborately subdivided • All terrestrial vertebrates, except birds, use a tidal ventilation system • Air moves in and out by the same route

12. Ventilation in Frogs

13. Ventilation inTerrestrial Vertebrates • Inspiration in mammals • Create negative pressure in lungs • The rib cage is elevated • The diaphragm lowers • Thoracic pressure decreases to less than atmospheric pressure • Atmospheric pressure forces air into the lungs • Expiration in mammals • Create positive pressure in lungs • The rib cage is lowered • The diaphragm rises • Thoracic pressure increases to more than atmospheric pressure • Forces air out the lungs

14. Lungs • Birds use a one-way ventilation mechanism in lungs • Results in a higher partial pressure of oxygen in the lungs • Oxygen uptake with each breath is greater than in other vertebrates

15. Respiratory System in Birds

16. Human Respiratory System • As air moves through upper respiratory system • It is filtered to free it of debris • Warmed, and • Humidified • When air reaches lungs • It is at body temperature, and • Its humidity is 100%

17. The Human Respiratory Tract

18. Human Respiratory System • Air passes from pharynx through glottis • Larynx and trachea • Permanently held open by cartilage rings • Facilitates movement of air • When food is swallowed • The larynx rises, and • The glottis is closed by the epiglottis • Backward movement of soft palate covers the entrance of nasal passages into the pharynx

19. Human Respiratory System • Trachea divides • Forms two primary bronchi • Bronchi enter the right and left lungs • Bronchi branch until there are a great number of tiny bronchioles • Each bronchiole terminates in an elongated space enclosed by alveoli

20. Ventilation • Humans breathe using a tidal mechanism • Volume of thoracic cavity and lungs is increased by muscle contractions that lower the diaphragm and raise the ribs • Create negative pressure in the thoracic cavity and lungs, and then air flows into the lungs during inspiration

21. Inspiration Versus Expiration

22. External and Internal respiration

23. Hemoglobin

24. Gas Exchange and Transport • Breathing stimulus • Increased H+ and CO2 concentrations in the blood • Not affected by O2 levels • Oxygen diffuses into pulmonary capillaries • Most combines with hemoglobin in red blood cells to form oxyhemoglobin • CO2 diffuses out of pulmonary capillaries • Most carbon dioxide is transported in the form of bicarbonate ion • Some carbon dioxide combines with hemoglobin to form carbaminohemoglobin

25. Hemoglobin Saturationin Relation to Temperature and Acidity

26. Respiration and Health • Upper Respiratory Tract Infections • Strep Throat • Streptococcus pyogenes • Sinusitis • Infection of sinuses • Tonsillitis • Infection of tonsils • Laryngitis • Infection of larynx

27. CommonBronchial and Pulmonary Diseases

28. Respiration and Health • Lower Respiratory Tract Infections • Acute bronchitis • Infection of primary and secondary bronchi • Pneumonia • Viral or bacterial infection of the lungs where bronchi and alveoli fill with fluid • Pulmonary tuberculosis • Caused by tubercle bacillus

29. Disorders • Pulmonary fibrosis • Fibrous connective tissue builds up in the lungs • Chronic bronchitis • Airways inflamed and filled with mucus • Emphysema • Alveoli are distended and walls are damaged reducing surface area available for gas exchange

30. Disorders • Asthma • Airways are unusually sensitive to specific irritants • When exposed to the irritants, the smooth muscles in the bronchioles undergo spasms • Lung Cancer • Begins with thickening and callusing of the cells lining the airways

31. Review • Gas Exchange Surfaces • Water Environments • Gills • Land Environments • Lungs • Human Respiratory System • Inspiration versus Expiration • Respiration and Health • Respiratory Disorders

32. Respiratory Systems