Respiration

1. Respiration Bio 1b Spring 2009 Hannah Nevins

2. Internal vs. external respiration • Internal or cellular respiration • Glucose and oxygen = carbon dioxide + water • External respiration or gas exchange • Breathing – inhale and exhale

3. Cellular respiration • Low PH High temperature • Concentration gradient • O2 increased in incoming blood relative to tissue •  O2 into tissue • CO2 increased in tissue relative to blood •  CO2 into blood

4. Gas Exchange • Partial pressures • PO2 • Respiratory Media • Water vs. air • Respiratory Surfaces • Gills – aquatic animals • Tracheal system – insects (terrestrial arthropods) • Lungs – terrestrial animals • Respiratory Pigments

5. Alveolus Alveolus PCO2 = 40 mm Hg PO2 = 100 mm Hg Fig. 42-28 PO2 = 40 PCO2 = 46 PCO2 = 40 PO2 = 100 Circulatory system Circulatory system PO2 = 40 PO2 = 100 PCO2 = 40 PCO2 = 46 PO2 ≤ 40 mm Hg PCO2 ≥ 46 mm Hg Body tissue Body tissue (a) Oxygen (b) Carbon dioxide

6. Partial pressures PO2 Respiratory Media Water vs. air Respiratory Surfaces Gills – aquatic animals Tracheal system – insects (terrestrial arthropods) Lungs – terrestrial animals Respiratory Pigments Gas Exchange

7. Respiration: Water vs. Air Coelom Gills Gills Tube foot Parapodium (functions as gill) (a) Marine worm (c) Sea star (b) Crayfish

8. Fig. 42-21a Parapodium (functions as gill) (a) Marine worm

9. Fig. 42-21b Gills (b) Crayfish

10. Fig. 42-21c Coelom Gills Tube foot (c) Sea star

11. Respiratory Surfaces Gills – aquatic animals (e.g. fish) Tracheal system – insects (terrestrial arthropods) Lungs – Simple – terrestrial gastropods, amphibians Mammalian lung Bird – air sacs Gas Exchange

12. Fluid flow through gill filament Oxygen-poor blood Anatomy of gills Oxygen-rich blood Gill arch Lamella Fig. 42-22 Gill arch Gill filament organization Blood vessels Water flow Operculum Water flow between lamellae Blood flow through capillaries in lamella Countercurrent exchange PO2 (mm Hg) in water 150 120 90 60 30 Gill filaments Net diffu- sion of O2 from water to blood 110 80 50 20 140 PO2 (mm Hg) in blood

13. Air sacs Tracheae Fig. 42-23 External opening Tracheoles Mitochondria Muscle fiber Body cell Air sac Tracheole Trachea Body wall Air 2.5 µm

14. Mammalian Lung: structure Branch of pulmonary vein (oxygen-rich blood) Branch of pulmonary artery (oxygen-poor blood) Terminal bronchiole Fig. 42-24 Nasal cavity Alveoli Left lung Trachea Right lung Bronchus Bronchiole Diaphragm Heart SEM Colorized SEM 50 µm 50 µm

15. Breathing ventilates the lung Rib cage expands as rib muscles contract Rib cage gets smaller as rib muscles relax Air inhaled Air exhaled Fig. 42-25 Lung Diaphragm INHALATION Diaphragm contracts (moves down) EXHALATION Diaphragm relaxes (moves up)

16. How do various animals breathe? • Snails & slugs (terrestrial gastropods) • Arthropods (Spiders & other insects) • Amphibians (frogs & salamanders) • Bird • Mammal

17. Book Lungs in spiders evolved from Book gills Horseshoe crab: book gills

18. Amphibians (frogs, salamanders) • Cutaneous – skin • Gills – Axoltl retains in adult • Buccopharyngeal – mouth (lungless salamanders – live in caves – why??)

19. Air sacs in Birds Air Air Anterior air sacs Fig. 42-26 Trachea Posterior air sacs Lungs Lungs Air tubes (parabronchi) in lung 1 mm EXHALATION Air sacs empty; lungs fill INHALATION Air sacs fill

20. Partial pressures PO2 Respiratory Media Water vs. air Respiratory Surfaces Gills – aquatic animals Tracheal system – insects (terrestrial arthropods) Lungs – terrestrial animals Respiratory Pigments Hemoglobin Gas Exchange

21. Respiratory Pigments: hold & transport oxygen • Hemoglobin – uses iron in red blood cells (vertebrates) – red in color • Myoglobin – in muscles (vertebrates) • Hemocyanin – uses copper (molluscs, arthropods) – colorless to blue • Hemerythrin – uses iron (Brachiopods, Pirulan worms) – colorless to violet/pink

22.  Chains Hemoglobin Fig. 42-UN1 Iron Heme  Chains

23. Body tissue CO2 transport from tissues CO2 produced Interstitial fluid CO2 CO2 Capillary wall Plasma within capillary CO2 H2O Hemoglobin picks up CO2 and H+ Red blood cell H2CO3 Fig. 42-30 Hb Carbonic acid HCO3– Bicarbonate H+ + HCO3– To lungs CO2 transport to lungs HCO3– HCO3– H+ + Hemoglobin releases CO2 and H+ Hb H2CO3 H2O CO2 CO2 CO2 CO2 Alveolar space in lung

24. 100 O2 unloaded to tissues at rest 80 O2 unloaded to tissues during exercise 60 Fig. 42-29a O2 saturation of hemoglobin (%) 40 20 0 20 40 80 100 0 60 Tissues during exercise Tissues at rest Lungs PO2 (mm Hg) (a) PO2 and hemoglobin dissociation at pH 7.4

25. 100 O2 unloaded to tissues at rest 80 O2 unloaded to tissues during exercise 60 O2 saturation of hemoglobin (%) 40 20 Fig. 42-29 0 0 20 40 60 80 100 Tissues during exercise Tissues at rest Lungs PO2 (mm Hg) (a) PO2 and hemoglobin dissociation at pH 7.4 100 pH 7.4 80 pH 7.2 Hemoglobin retains less O2 at lower pH (higher CO2 concentration) 60 O2 saturation of hemoglobin (%) 40 20 0 0 20 40 60 80 100 PO2 (mm Hg) (b) pH and hemoglobin dissociation

26. 100 pH 7.4 80 pH 7.2 Fig. 42-29b Hemoglobin retains less O2 at lower pH (higher CO2 concentration) 60 O2 saturation of hemoglobin (%) 40 20 0 0 20 40 60 80 100 PO2 (mm Hg) (b) pH and hemoglobin dissociation

27. Fig. 42-UN4

28. RESULTS Goat Pronghorn 100 90 80 Fig. 42-31 70 60 Relative values (%) 50 40 30 20 10 0 VO2 max Lung capacity Muscle mass Mitochon- drial volume Cardiac output

29. Body tissue CO2 transport from tissues CO2 produced Interstitial fluid CO2 Fig. 42-30a Capillary wall CO2 Plasma within capillary CO2 H2O Hemoglobin picks up CO2 and H+ Red blood cell H2CO3 Hb Carbonic acid HCO3– Bicarbonate H+ + HCO3– To lungs

30. CO2 transport to lungs HCO3– HCO3– H+ + Hemoglobin releases CO2 and H+ Fig. 42-30b Hb H2CO3 H2O CO2 Plasma within lung capillary CO2 CO2 CO2 Alveolar space in lung