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Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 44 Gas Exchange.

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Presentation on theme: "Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 44 Gas Exchange."— Presentation transcript:

1 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 44 Gas Exchange

2 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Respiration The exchange of gases between an organism and its environment Organismic respiration –Takes place in animals –O 2 taken up and CO 2 excreted Aerobic cellular respiration –Takes place in mitochondria –O 2 is necessary for citric acid cycle

3 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Simple diffusion Passive movement of particles from a region of higher concentration to a region of lower Provides gas exchange for small, aquatic organisms such as sponges, hydras, and flatworms

4 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Comparison of gas exchange in air and water Air –Contains a higher concentration of molecular oxygen than water –Oxygen diffuses more rapidly through air than water –Less energy needed to move air over gas exchange surface

5 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Adaptations for gas exchange Body surface –Small aquatic animals exchange gases by diffusion, requiring no specialized respiratory structures –Some invertebrates, including most annelids, and many amphibians exchanges gases across the body surface

6 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Gas exchange across body surface

7 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Adaptations for gas exchange, contd Trachae –In insects and some other anthropods, air enters trachae through openings called spiracles –Trachae branch and extend to all regions of the body

8 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Gas exchange across tracheal tubes

9 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Adaptations for gas exchange, cont. Gills –Moist, thin projections of the body surface found mainly in aquatic animals –Countercurrent exchange system maximizes O 2 into the blood and CO 2 out of the blood

10 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Gas exchange across gills

11 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Adaptations for gas exchange, cont. Lungs –Terrestrial vertebrates have lungs and some means of ventilating them –Lungs are respiratory structures that develop as ingrowths of body surface or from wall of a body cavity

12 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Gas exchange across lungs

13 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Comparison of vertebrate lungs

14 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange How bird lungs function

15 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Mammalian respiratory system Includes the lungs and airways Lung occupies pleural cavity and is covered with a pleural membrane Breath of air passes in sequence –Nostrils, nasal cavities, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli

16 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange The human respiratory system

17 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Structure of alveoli

18 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Mechanics of breathing Diaphragm contracts and chest cavity expands Respiratory centers in the medulla and pons regulate respiration –Stimulated by chemoreceptors –An increase in hydrogen ions and low oxygen concentration

19 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Mechanics of breathing

20 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Role of hemoglobin in oxygen transport Respiratory pigment in vertebrate blood Almost 99% of the O 2 in human blood is transported as oxyhemoglobin (HbO 2 )

21 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Gas exchange in the lungs and tissues

22 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Oxygen-carrying capacity Maximum amount of O 2 that can be transported by hemoglobin Oxygen content Actual amount of O 2 bound to hemoglobin Percent oxygen saturation Ratio of O 2 content to O 2 carrying capacity

23 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Oxygen-hemoglobin dissociation curve Shows that as O 2 concentration increases, there is progressive increase in hemoglobin that combines with O 2 Bohr effect Oxyhemoglobin dissociates more readily as CO 2 increases

24 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Oxygen-hemoglobin dissociation curves

25 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Carbon dioxide transport

26 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Hyperventilation Reduces the concentration of CO 2 in the alveolar air and the blood Decompression in divers Rapid decrease in barometric pressure can cause decompression sickness Diving mammals have high concentrations of myoglobin

27 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Deep diver

28 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 44 Gas Exchange Affects of pollution on the respiratory system Ciliated mucous lining traps inhaled particles Inhaling polluted air results in bronchial constriction –Increased mucous secretion –Damage to ciliated cells –Coughing


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