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Respiratory system

Respiratory system. Gas exchange. Respiration involves various processes: Ventilation - breathing External respiration - gas exchange between the air and the blood in the lungs Internal respiration - gas exchange between the blood and the tissue fluid. Gas exchange.

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Respiratory system

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  1. Respiratory system

  2. Gas exchange • Respiration involves various processes: • Ventilation- breathing • External respiration- gas exchange between the air and the blood in the lungs • Internal respiration- gas exchange between the blood and the tissue fluid

  3. Gas exchange Gas exchange needsmoist respiratory surfacesto occur. Aquatic organisms spend up to 25% of the energies to extract air from water. Terrestrial organisms need to moisten constantly the respiratory surfaces.

  4. Direct respiration through surfaces Small aquatic animals as cnidarians and plathelminthes exchange gases directly with the external environment.

  5. Branchial respiration Aquatic invertebrates (mollusks and crustacean) and vertebrates (fish) have specialized organs for gas exchange called gills.

  6. Direct respiration through canals Insects use tracheaeto deliver oxygen directly to muscles.

  7. Direct respiration through canals Terrestrial vertebrates and marine mammals usually moist air before it enters the lungs.

  8. Countercurrent exchange Gills Water moves across the gills near the mouth. Fish use countercurrent exchangeto transfer oxygen efficiently to blood.

  9. Lungs The respiratory system includes all structures that bring air to the lungs. The air is warmed and humidified in the nasal cavity and mouth. The glottis opens and the tracheaconnects the larynxto the two bronchi.

  10. Bronchioles and alveoli Bronchi branch into bronchioles that end in alveoli. Alveoli compose the lung and are the site for gas exchange with blood.

  11. Smoking is dangerous Short-term effects: nagging cough, diminished sense of smell, premature aging of the skin. Long-term effects: cancer, heart diseases, aneurysm, pulmonary diseases, stroke. Other effects: chance of premature birth, low birth weight and stillbirth.

  12. Inspiration and expiration Inspiration consists of muscle contractions that lower the diaphragm and raise the ribs. The negative pressurecauses the air to flow in.

  13. Inspiration and expiration During expiration the diaphragm muscles relax and air flows out as the inner pressure increases.

  14. Respiratory centers Breathing rhythms are automatically controlledby the respiratory center located in the medulla oblongata, in the lowermost part of the brain stem. Changing in blood pH can cause variation in the respiration speed rate.

  15. Respiration and physical exercise During exercise the respiratory system makes adjustments in response to the duration and intensity of the effort. During exercises the amount of O2 needed and CO2 produced increase. Consequently the blood flow in both muscles and lungs must also increase.

  16. External and internal respiration External and internal respiration take advantage from the spontaneous gas diffusionbetween air and blood. In the lungs the oxygen partial pressure(PO2) is higher while PCO2 is lower than in the blood. Hence CO2 diffuses out of the blood into the lungs and O2 diffuses out of the lungs into the blood.

  17. Hemoglobin Hemoglobin (Hb) is a red blood cells protein involved in the transport of gases. • External respiration • Hb combines with O2 to form HbO2. • HCO3- forms H2CO3 which breaks down into H2O and CO2. • Internal respiration • HbO2 releases O2 into cells. • Hb combines with CO2. • CO2 combines with water to form H2CO3 which then becomes HCO3-.

  18. External and internal respiration

  19. Respiratory disorders In restrictive pulmonary disorders, lung capacity is reduced as the lungs have lost their elasticity. In obstructive pulmonary disorders, air does not flow easily in the airways. Common types are bronchitis, emphysema and asthma. Lung cancers are characterized by thickening and callusing of cells lining the bronchi, loss of cilia, formation of a tumor that eventually metastasizes.

  20. Online resources • http://www.abpischools.org.uk/page/modules/breathingandasthma/.cfm?coSiteNavigation_allTopic=1 • http://www.wwnorton.com/college/biology/discoverbio5/ch/28/animations.aspx (Structure and Function of the Lungs; n OxygenBinding by Hemoglobin) • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter25/animation__gas_exchange_during_respiration.html • http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/respiration/respirationrev1.shtml • http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/understanding_organisms/fitness_healthrev1.shtml (page3)

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