Download 27.2_Respiration

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Relate Cause and Effect Why do some animals
actively pump water over their gills
Interpret Visuals Contrast the structures of
amphibian, reptilian, and mammalian lungs
Explain Describe the events that occur when a
mammal respires including the path of air through
the lungs.
CH 27 ANIMAL SYSTEMS I
27.2 Respiration
Gas Diffusion and Membranes
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Gases diffuse most efficiently across a thin, moist
membrane that is permeable to those gases
Larger the surface area membrane, the more
diffusion that can occur.
Requirements for Respiration
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Large surface area of moist, selectively permeable
membrane
Difference in relative concentrations of oxygen and
carbon dioxide on either side of the respiratory
membrane.
Respiratory Surfaces of Aquatic Animals
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Some aquatic invertebrates and a few chordates
rely on diffusion of oxygen and carbon dioxide
through their outer body covering.
Respiratory Surfaces of Aquatic Animals
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Many aquatic invertebrates and most aquatic
chordates exchange gases through gills
Gills
 Feathery
structures that expose a large surface area of
thin, selectively permeable membrane to water
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Capillaries
 Network
of tiny, thin-walled blood vessels.
Respiratory Surfaces of Aquatic Animals
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May actively pump water over their gills as blood
flows through inside
Gas exchange occurs as water passes over the gills.
Respiratory Surfaces of Aquatic Animals
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Lungs
 Organs
that exchange oxygen and carbon dioxide
between blood and air

Aquatic reptiles and aquatic mammals, must hold
their breath underwater.
Respiratory Surfaces in Land Invertebrates

Wide variety of respiratory structures
 Respire
across their skin
 Mantle cavity
 Book lungs
 Tracheal tubes.
Book Lungs

Which are made of parallel, sheetlike layers of thin
tissues containing blood vessels.
Tracheal Tubes
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Air enters and leaves the system through openings in
the body surface called spiracles
Most invertebrates.
Lung Structure in Vertebrates
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Lung structure in terrestrial vertebrates varies
Processes of inhaling and exhaling are similar
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Inhaling brings oxygen-rich air through the trachea
(airway) into the lungs
Oxygen diffuses into the blood through lung
capillaries
Carbon dioxide diffuses out of capillaries into the
lungs
Oxygen-poor air is then exhaled.
Amphibian, Reptilian, and Mammalian
Lungs
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Typical amphibian lung is little more than a sac with
ridges.
Amphibian, Reptilian, and Mammalian
Lungs
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Reptilian lungs are divided into chambers
 Increase
the surface area for gas exchange.
Amphibian, Reptilian, and Mammalian
Lungs

Mammalian lungs branch extensively
 Filled
with Alveoli.

Alveoli
 Provide
enormous surface area for gas exchange
 Enable mammals to take in the large amounts of
oxygen required by their high metabolic rates.
Bird Lungs
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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
 Highly
efficient
 Enables flight, at high altitude for extended time.