Outline 25 2008 Circulation and gas exchange

Outline 25 2008 Circulation and gas exchange - Lecture 25:...

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Lecture 25: CIRCULATION AND GAS EXCHANGE IN ANIMALS Summary. To obtain oxygen and rid themselves of CO 2 all organisms depend upon efficient mechanisms for exchange of gasses across moist membranes. Gas exchange by diffusion alone, however, is sufficient only for very small organisms, or those with flattened morphology. For larger organisms, specialized gills, lungs, or air capillaries (trachea) have evolved, and a circulatory system is essential in large organisms to move dissolved gasses from point to point. Mechanical constraints have guided the evolution of aquatic respiratory organs as opposed to terrestrial. In many animals, respiratory organs function together with internal transport systems, including the respiratory pigments in the blood. In vertebrates, gasses are transported to tissues by the blood. The circulatory system moves gasses and other dissolved substances to the tissues and back to the lungs. Hemoglobin plays a major role in binding oxygen and moving it to the tissues. Carbon
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This note was uploaded on 09/13/2009 for the course BIO 1110 taught by Professor Randywayne during the Fall '09 term at Cornell.

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Outline 25 2008 Circulation and gas exchange - Lecture 25:...

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