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Lesson Overview 27.2 Respiration THINK ABOUT IT Humans can drown because our lungs can t extract the oxygen we need from water. Most fishes have the opposite ... – PowerPoint PPT presentation

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Title: Lesson Overview


1
Lesson Overview
  • 27.2 Respiration

2
THINK ABOUT IT
  • Humans can drown because our lungs cant extract
    the oxygen we need from water. Most fishes have
    the opposite problem out of water, their gills
    dont work.
  • How are these different respiratory systems
    adapted to their different functions?

3
Gas Diffusion and Membranes
  • Animals have evolved respiratory structures
    that help movement of these gases by passive
    diffusion.
  • Substances diffuse from an area of higher
    concentration to an area of lower concentration.
  • Gases diffuse most efficiently across a thin,
    moist membrane that is permeable to those gases.
  • The larger the surface area of that membrane,
    the more diffusion can take place.

4
Requirements for Respiration
  • Respiratory structures provide a large surface
    area of moist, selectively permeable membrane.
  • Respiratory structures maintain a difference in
    concentrations of oxygen carbon dioxide
    promoting diffusion.
  • Because respiratory surfaces are moist, an
    animals breath condenses into fog when the air
    outside is very dry.

5
Gas Exchange
  • What characteristics do the respiratory
    structures of all animals share?

6
Gas Exchange
  • What characteristics do the respiratory
    structures of all animals share?
  • Respiratory structures provide a large surface
    area of moist, selectively permeable membrane.
  • Respiratory structures maintain a difference in
    the relative concentrations of oxygen and carbon
    dioxide on either side of the respiratory
    membrane, promoting diffusion.

7
Respiratory Surfaces of Aquatic Animals
  • Many aquatic invertebrates most aquatic
    chordates exchange gases through gills.
  • Gills are feathery structures that expose a
    large surface area of thin, selectively permeable
    membrane to water.
  • Gill membranes is a network of tiny,
    thin-walled blood vessels called capillaries.

8
Respiratory Surfaces of Aquatic Animals
  • Many animals actively pump water over their
    gills as blood flows through inside.
  • As water passes over the gills, gas exchange is
    completed within the gill capillaries.

9
Respiratory Surfaces of Aquatic Animals
  • Aquatic reptiles aquatic mammals, such as
    whales, breathe with lungs and must hold their
    breath underwater.
  • Lungs are organs that exchange oxygen and carbon
    dioxide between blood and air.

10
Respiratory Surfaces of Aquatic Animals
  • Some aquatic invertebrates, such as cnidarians
    flatworms have thin-walled bodies rely on air
    diffusion through their outer body covering.
    (skin breathers)
  • A few aquatic chordates, including lancelets,
    some amphibians, and even some sea snakes, rely
    on skin to breath ex.) lungless frog

11
Respiratory Surfaces of Aquatic Animals
  • How do aquatic animals breathe?

12
Respiratory Surfaces of Aquatic Animals
  • How do aquatic animals breathe?
  • Many aquatic invertebrates and most aquatic
    chordates other than reptiles and mammals
    exchange gases through gills.
  • Aquatic reptiles and aquatic mammals, such as
    whales, breathe with lungs and must hold their
    breath underwater.

13
Respiratory Surfaces in Land Invertebrates
  • Terrestrial invertebrates have a wide variety of
    respiratory structures.
  • Some land invertebrates, such as earthwormsskin
    breather/ land snailsmantle cavity, which is
    lined with moist tissue and blood vessels.

14
Respiratory Surfaces in Land Invertebrates
  • Spiders respire using organs called book lungs,
    which are made of parallel, sheetlike layers of
    thin tissues containing blood vessels.

15
Respiratory Surfaces in Land Invertebrates
  • Most insects respire using a system of tracheal
    tubes that extends throughout the body.
  • Air enters and leaves the system through
    openings in the body surface called spiracles.

16
Lung Structure in Vertebrates
  • Inhaling O2 air into the lungs.
  • Inside the lungs, O2 diffuses into the blood
    through lung capillaries.
  • Co2 diffuses out of capillaries into the lungs.
  • Oxygen-poor air is then exhaled.

17
Amphibian, Reptilian, and Mammalian Lungs
  • The internal surface area of lungs increases
    from amphibians to reptiles to mammals.

18
Amphibian, Reptilian, and Mammalian Lungs
  • A typical amphibian lung is little more than a
    sac with ridges.

19
Amphibian, Reptilian, and Mammalian Lungs
  • Reptilian lungs are divided into chambers that
    increase the surface area for gas exchange.

20
Amphibian, Reptilian, and Mammalian Lungs
  • Mammalian lungs branch extensively and are
    filled with bubblelike structures called alveoli.

21
Amphibian, Reptilian, and Mammalian Lungs
  • Alveoli provide an enormous surface area for gas
    exchange, and enable mammals to take in the large
    amounts of oxygen required by their high
    metabolic rates.

22
Bird Lungs
  • In birds, the lungs are structured so that air
    flows mostly in only one direction, so no stale
    air gets trapped in the system.
  • Gas exchange surfaces are continuously in
    contact with fresh air.
  • This highly efficient gas exchange helps birds
    obtain the oxygen they need to power their flight
    muscles at high altitudes for long periods of
    time.

23
Respiratory Surfaces of Terrestrial Animals
  • What respiratory structures enable land animals
    to breathe?

24
Respiratory Surfaces of Terrestrial Animals
  • What respiratory structures enable land animals
    to breathe?
  • Respiratory structures in terrestrial
    invertebrates include skin, mantle cavities, book
    lungs, and tracheal tubes.
  • What respiratory structures enable land animals
    to breathe?
  • But all terrestrial vertebratesreptiles, birds,
    mammals, and the land stages of most
    amphibiansbreathe with lungs.
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