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Unformatted text preview: RESPIRATORY SYSTEM Gas exchange = uptake of O 2 and discharge of CO 2 Respiratory medium = source of O 2 (air for terrestrial animals, water for aquatic animals) Water- keeps respiratory cells moist, but O 2 concentration is low Air- High O 2 concentration and easier to pump than water, but difficult to keep cells moist Respiratory surface A. gases must DIFFUSE across membrane, so resp. surfaces are usually thin with large surface area to maximize gas exchange B. Cells must remain moist to maintain plasma membrane, so respiratory surfaces are moist. O 2 and CO 2 diffuse across these surfaces after dissolving in water. SIMPLE ANIMALS (sponges, cnidarians, flatworms) Gases diffuse across plasma membrane of every cell in the body MORE COMPLEX ANIMALS – Bulk of body doesn’t have access to respiratory medium Earthworms, amphibians - Respiration across entire outer skin...
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This note was uploaded on 02/11/2012 for the course ZOOLOGY 152 taught by Professor Stephengammie during the Fall '11 term at University of Wisconsin.
- Fall '11