Respiration

1. Respiration Chapter 35

2. Aerobic vs. Anaerobic Life • aerobic • requires oxygen to survive • oxygen  carbon dioxide • anaerobic • does not require oxygen for survival • uses other elements in place of oxygen • Respiratory Interfaces • membranes across which gas exchange occurs • critical factors are moisture and surface area • thin and very extensive • work very closely with circulatory system  highly vascularized • components of respiration • breathing • inspiration vs. expiration • external respiration • exchange between air and blood; occurs within lungs • internal respiration • exchange between blood and tissues

3. Page 650 External and internal respiration

4. Fig. 35.12 External and internal respiration

5. Respiration in Animals • sponges, cnidaria, platyhelminthes, echinoderms • simple body interface  breath through body wall • annelids, mollusks, amphibians • complex body interface  breath through skin • circulatory sys., moist environment, and/or gills work with skin • amphibians: skin, gills, and lungs Fig. 35.2 A complex body interface Fig. 35.1 A simple body interface

6. insects • air enters through spiracles highly branched tracheal system • aquatic insects have external tracheal gills Fig. 35.5 Tracheal system of insects

7. fish and crustaceans • gills and gill structure • gill arches and filaments • carapace or operculum • transport of oxygen is aided by hemocyanin or hemoglobin • countercurrent vs. parallel vs. crosscurrent exchange The structure and function of gills

8. A comparison of the efficiency of countercurrent and parallel exchange

9. Fig. 35.4 Anatomy of gills in bony fishes

10. terrestrial vertebrates • internal respiratory interfaces  prevent desiccation • lungs are primary organs for gas exchange • Vertebrate Lungs • highly branched arrangement of small tubes • spongy, moist • tubes terminate in clusters of air sacs called alveoli • alveoli are associated with capillaries (vascularized) • muscular contractions inflate and deflate lungs • amphibian lungs are simple • alveoli not highly interconnected  often gulp air • reptile lungs are more complex • alveoli highly interconnected • bird lungs • possess anterior and posterior air sacs, plus lungs • no alveoli; air flows through the lungs, not in and out • crosscurrent exchange Fig. 35.3 Respiratory systems

11. bird lungs • possess anterior and posterior air sacs, plus lungs • no alveoli; air flows through the lungs, not in and out • crosscurrent exchange • adaptations for flight and extracting O2 at high altitudes Fig. 35.10 Respiration in birds

12. Human Respiratory System • lungs • consist mostly of many small tubes • primary, secondary, tertiary bronchi • bronchioles • bronchioles terminate in alveoli (with supporting capillaries) • actual gas exchange occurs here • right lung larger than left • right divided into 3 lobes, left into 2 • lie in thoracic cavity • protected by ribs and supporting tissues • surrounded by tissues called pleurae • protection • help maintain correct pressure within lungs • diaphragm and rib muscles (intercostals) • responsible for inhalation and exhalation

13. path of air flow through the body • nasal passages nasopharynx pharynx  glottis  larynx (past vocal cords)  trachea  primary bronchi (in lungs now)  secondary bronchi  tertiary bronchi  bronchioles  alveoli (gas exchange) • air breathed through mouth  pharynx • mucous linings and cilia • filter out dust particles, microbes, and other debris • keep respiratory system moist • entire respiratory system is prone to numerous problems and infections

14. Fig. 35.6 The human respiratory system

15. Fig. 35.14 Common bronchial and pulmonary diseases

16. resting exchange of air (0.5 liters) • vital capacity (highly variable; about 5 liters) • residual air • air that is always in the lungs  helps maintain correct pressure (about 1.5 liters) • inhalation (inspiration) process vs. exhalation (expiration) process Fig. 35.15 Normal vs. diseased lungs

17. Fig. 35.7 Inspiration (inhalation) Fig. 35.8 expiration (exhalation)

18. Exchange of Gases • atmospheric vs. partial pressure • both decrease with altitude • gas exchange occurs across moist surface of alveoli • very highly vascularized capillary beds • exchange occurs by simple diffusion • O2 and CO2 move from high concentration to low conc. • does not require energy (passive process) • efficiency increased by countercurrent exchange • Transport of Oxygen • red blood cells in circulatory system • transport and deliver O2 to all body tissues • hemoglobin aids in transport • 1,000’s are packed onto each red blood cell • four polypeptide chains, each with a heme group • heme groups contain an Fe molecule • each Fe molecule can bind one oxygen molecule

19. association and dissociation of O2 with hemoglobin is complex • pH (Bohr effect) • pH in tissues decreases  dissociation of O2 with hemoglobin is increased • more O2 released to tissues • partial pressure of oxygen • partial pressure of carbon dioxide • temperature Fig. 35.13 Hemoglobin

20. Control of Breathing • conscious control of rate and volume of breathing – to a point • involuntary control overall • nervous system • inspiratory and expiratory centers in brain • mostly in medulla portion of brain • chemoreceptors • clusters of cells that detect changes in blood chemistry • brain vs. heart