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Unit 16 (Ch. 22) Gas Exchange & Excretion

Unit 16 (Ch. 22) Gas Exchange & Excretion. How do organisms: Obtain oxygen and eliminate carbon dioxide? (or vice versa…in plants?) Maintain osmotic balance? Excrete nitrogenous waste products?. 300. Gas Exchange (ch 22.1). What gases are exchanged ? O 2 CO 2

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Unit 16 (Ch. 22) Gas Exchange & Excretion

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  1. Unit 16 (Ch. 22)Gas Exchange & Excretion How do organisms: Obtain oxygen and eliminate carbon dioxide? (or vice versa…in plants?) Maintain osmotic balance? Excrete nitrogenous waste products? 300

  2. Gas Exchange (ch 22.1) • What gases are exchanged ? • O2 • CO2 • By which process are gases exchanged? • diffusion

  3. Gas Exchange • What conditions are required for gas exchanged? • gas must be dissolved in a liquid • large surface area • Why? • to maximize exchange • protection of structures • Which system does the respiratory system often work with in animals? • circulatory (transport) system

  4. Gas Exchange in Unicellular & Simple Multicellular Organisms • How is gas exchange carried out in simple organisms? • diffusion directly with moist environment

  5. Gas Exchange in Plants • Where does gas exchange occur in plants? • no specialized gas transport system b/c occurs @ different locations • roots • root hairs • stems • lenticels • leaves • gases enter/exit through stomataand move into air spaces of spongy layer • exchange occurs at moist surface of cells surrounding air spaces

  6. Gas Exchange in More Complex Animals • Usually carried out by respiratory system. • acquire O2 from environment, distribute it through body, & discharge CO2 • “respiration”

  7. Gas Exchange in Animals • 3 “types” of respiration: • external respiration: • breathing • internal respiration: • exchange of O2 & CO2 between air sacs & capillaries (or cells) • cellular respiration: • C6H12O6 + 6O2→ 6H2O + 6CO2 + energy (ATP)

  8. Earthworm • gases diffuse through moist skin

  9. Grasshopper • air enters spiracles (openings) • lead to tracheae (tubes) • tracheae branch repeatedly • ending in moist tracheoles (air sacs) • gas exchange (diffusion) – aided by muscle mvmt

  10. Fish • operculum or gill cover • protection • H2O enters mouth & flows over gills • CO2 diffuses blood  H2O • O2 diffuses H2O  blood

  11. Fish • How does the amount of O2 dissolved in water change in relation to water temp.? • Which of these descriptions best explains the decrease in the breathing rate of the goldfish? • The demand for O2 increased. • The rate of metabolic activity decreased. • The demand for CO2 decreased. • The fish's activity levels increased. Virtual Fish Respiration Lab

  12. Respiration in Humans • What path does air follow when inhaling? • nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli • gas exchange: alveoli ↔ capillaries Epiglottis prevents food from entering trachea. How are alveoli an adaptation? What is the function of the cartilaginous rings around the trachea? Respiration Animation Gas Exchange Animation 1 capillaries

  13. Human Respiratory System capillaries

  14. RESPIRATION IN HUMANS • What happens in the lungs during gas exchange? • alveoli have high level of O2 & low level CO2 • O2 diffuses from alveoli  blood in capillaries (combines w/ hemoglobin in red blood cells) • blood in capillaries has high level of CO2 & low level of O2 • CO2 diffuses from blood  alveoli • & is exhaled

  15. RESPIRATION IN HUMANS • What happens in the cells/ tissues during gas exchange? • cells/tissues have high level of CO2 & low level of O2 • CO2 diffuses from cells/tissues  blood in capillaries • blood in capillaries has high level of O2 & low level of CO2 • O2 diffuses from blood in capillaries  cells/tissues

  16. Gas Exchange Animation 1 Gas Exchange Animation 2 Gas Exchange Animation 3

  17. Respiration in Humans • Do you have to remember to breathe? • No, medulla (brain stem) controls breathing. • responds to blood’s CO2 levels • CO2 too high  breathe faster

  18. Respiration in Humans • What happens to your breathing rate when you exercise? Why? • increases to adjust rate of gas exchange to needs of cells • b/c CO2 levels increase & O2 decrease

  19. Respiration in Humans • What happens to the diaphragm and ribs during inhalation? • diaphragm contracts (pulls down/flattens) • ribs raised (move up/out) • Does the chest cavity gets bigger or smaller? • bigger (expands) • What happens to air pressure in the lungs? • becomes lower inside than outside • Which way does air move? • air rushes in

  20. Respiration in Humans • What happens to the diaphragm and ribs during exhalation? • diaphragm is relaxed (pushes up/arches) • ribs lowered (move down/in) • Does the chest cavity gets bigger or smaller? • smaller (compresses) • What happens to air pressure in the lungs? • becomes higher inside than outside • Which way does air move? • air rushes out

  21. RESPIRATION IN HUMANS: CONTROL OF BREATHING Remember… “High, low…” Pressure higher outside, lower inside Pressure higher inside, lower outside

  22. RESPIRATION IN HUMANS: CONTROL OF BREATHING Kid's Health Respiratory System & Breathing

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