bio LOBJ2[1]

bio LOBJ2[1] - Learning objectives for exam 2 Gas Exchange...

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Learning objectives for exam 2 Gas Exchange in Animals 35. Define gas exchange and distinguish between a respiratory medium and a respiratory surface. Gas Exchange : is the uptake of oxygen from the environment and the release of carbon dioxide. A Respiratory medium is the source of oxygen. Ex. Air, Water The Respiratory surface is the area of the animal’s body that exchanges gas and must be moist. 36. Describe the general requirements for a respiratory surface and list a variety of respiratory organs that meet these requirements. It must be moist, and it must supply O2 and expel CO2 for the entire body. (Thus must have an adequate surface area) Organs : Gills, Tracheae, Lungs, Entire Skin (through diffusion) 37. Describe respiratory adaptations of aquatic animals. Gills: which are outfoldings of the body surface that are suspended in the water. With gills comes Ventilation : which increases the water flow past the gills 38. Describe the advantages and disadvantages of water as a respiratory medium. Advantage : There is no problem keeping the plasma membranes of the respiratory surface cells moist. Disadvantage : O2 concentrations are law, and the warmer and saltier the water, the less dissolved O2 it can hold 39. Describe countercurrent exchange and explain why it is more efficient than the concurrent flow of water and blood. Countercurrent exchange : Blood flows in the direction opposite to the movement of water past the gills. This makes it possible to transfer 02 to the blood by efficiently. -------------- Water | | | | | | | | | | | ----transfer of 02 -----------Blood As the blood moves through a gill capillary It becomes more and more loaded with 02, as well as simultaneously encountering water with higher 02 concentrations (because it just entered the gills) 40. Describe the advantages and disadvantages of air as a respiratory medium and explain how insect tracheal systems are adapted for efficient gas exchange in a terrestrial environment. Advantages: Air has a much higher concentration of O2 O2 and CO2 diffuse much faster in air, don’t have to be ventilated as vigorously as gills.
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As the respiratory system removes O2 from the air and expels CO2, diffusion rapidly brings more O2 to the respiratory surface and carries CO2 away. Disadvantages: Continuously loses water to the air through evaporation. Insects Tracheal systems : is made up of air tubes that branch throughout the body. The finest branches extend to the surface of nearly every cell, where gas is exchanged by diffusion across the moist epithelium that lines the terminal ends of the tracheal system. This delivers air directly to body cells. 41. For the human respiratory system, describe the movement of air through air passageways to the alveolus, listing the structures that air must pass through on its journey. First Air enters through the Nostrils
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This note was uploaded on 01/26/2012 for the course BIO 1421 taught by Professor Farr during the Fall '08 term at Texas State.

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bio LOBJ2[1] - Learning objectives for exam 2 Gas Exchange...

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