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campbell42hand - Circulation and Gas Exchange Circulatory...

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Circulation and Gas Exchange Circulatory systems Function: Transport of materials throughout body (Gases,hormones, immune cells, heat exchange) Circulatory systems allow efficient exchange between cells of an organism and with its environment Organisms utilize increased branching/folding and flattening of exchange surface to maximize surface area/volume ratios Simple circulatory system: Gastovascular cavity Can function for digestion and distribution of materials The GV cavity of jelly fish are highly branched for optimal exchange Can function for digestion and distribution of materials Flatworm body shape serves to maximize surface area/volume ratio Open and Closed Circulatory Systems Both systems have three basic components: A circulatory fluid (blood or hemolymph) A set of tubes (blood vessels) A muscular pump (the heart) In insects, other arthropods, and most molluscs, blood bathes the organs directly in an open circulatory system In an open circulatory system, there is no distinction between blood and interstitial fluid, and this general body fluid is more correctly called hemolymph In a closed circulatory system, blood is confined to vessels and is distinct from the interstitial fluid Closed systems are more efficient at transporting circulatory fluids to tissues and cells Three fluid compartments Intracellular fluid (ICF): Inside cells Extracellular fluid (ECF) Plasma: Fluid portion of blood Interstitial fluid: fluid between cells and circulatory system
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Components of circulatory system Blood Heart : Pump Arterial system : Delivery vessels Carry blood away from heart Capillaries : Exchange vessels between tissues and circulation Venous system : return vessels Return blood to heart Vertebrate circulatory system Single circulation found in bony fishes, rays, and sharks Blood enters atria…to ventricle…to gills for gas exchange… delivery of oxygen to tissues Drop of blood pressure at gill capillary bed limits blood flow Swimming increases circulation Double circulation found in other vertebrates Right side of heart pumps blood for gas exchange Left side pumps oxygenated blood to rest of body Increases pressure for blood to flow to all organs Different vertebrates have developed specific adaptations Amphibians have three chamber heart (two atria;one ventricle) Ridge in ventricle diverts most oxygen poor blood to lung and skin capillaries while most oxygen-rich blood diverted to systemic capillaries Blood diverted to skin exchange while under water Reptiles (sans birds) have three chamber heart (two atria;one ventricle)with septum Allows control of blood flow to be shifted to systemic circulation while submerged (lungs ineffective) Mammals and birds have four chamber heart Key adaptation for high energy consuming endotherms
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How does Blood flow?
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This note was uploaded on 07/07/2010 for the course BIOLOGY bild 2 taught by Professor Schroeder during the Spring '09 term at UCSD.

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campbell42hand - Circulation and Gas Exchange Circulatory...

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