5 gas exchange
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Gas Exchange I. Introduction
A. Why?
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B. Forces & Factors 1. What forces drive gas exchange?
Figure 42.23
2. What factors help to maximize exchange?
C. Transport
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II. Strategies A. Direct
Poriferans, Cnidarians, and Platyhelminthes
Figure 33.4
Constant water movement
Simple thin structure
What would be required to lead this life style?
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B. Gills 1. Structure
Mollusca to Vertebrata
Figure 42.22
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Fish Gills
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2. Forces
Ram ventilation vs. Gulping Advantages vs. Disadvantages
a. Passive to b. Active
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Circulation of water coupled with perfusion of blood
Figure 42.23
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swim bladder in bony fishes via the gas gland
Figure 34.16
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C. Tracheal Systems 1. Insecta
Figure 42.24
direct oxygen delivery system to the
muscle fibers
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2. Chordata a. Amphibians
Circulate air to lungs from mouth
and skin ==PP breathers
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b. Reptilians PP breathers
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c. Avians Negative pressure breathers move air into
their lungs and air sacs
Figure 42.27
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d. Mammalians
i. Air tubes Negative breathers use
muscle contractions to
move air
Figure 42.25
pseudostratified ciliated columnar with goblet cells
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ii. Lungs
alveoli for gas exchange Type I, Type II cells,
and Dust cells
Figure 42.25
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Lung expansion == muscle contraction
Quiet versus Forced Inhalation vs. Exhalation
Figure 42.28
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iii. Control
Pons, Medulla Oblongata, and the Hypothalamus
Figure 42.29
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iv. Transport O2 partial gas pressures
Figure 42.30
Figure 42.31a & b
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Respiratory pigments transport oxygen and also buffer
CO2 is transported via other mechanisms
Dissolved in plasma about 7%
Bound to globin about 23%
Travels via the bicarbonate shuttle about 70%
Figure 42.32
iv. Transport CO2
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Quantity doesnt mean Quality.
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