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Unformatted text preview: Circulatory System 8/1/08 Fri Circulatory system job: Cells need to be bathed in an aqueous medium Small organisms like hydra have high SA/V and are only 2 cell layers think ocean is their aqueous medium Larger animals must have a way of transporting fuel and oxygen to the cell and waste away from the cell- circulation@ Functions : Facilitate gas exchange (O2 and CO2) between the outside environment and the mitochondria of cells Carry hormones, marcromolecules and other biomeolecules from where they are made to effectors cells Carry waste products from cell to excretory system Predict the form! Lungs/ gills/skin-primary sites of gas exchange for different vertebrates Large surface area Paired with high blood flow Small diffusion distance across capillary in lung/gill/skin as well as at the cell Oxygen pathway: moving from ambient air to mitochondria (ventilation cirulation Circulatory system 3basic types Gastrovascular cavities internal transport digestion and distribution (Cnidarians :jellyfish/hydras) Body cavity with a single opening to the outside Food is digested in the cavity and absorbed by body cells Wastes are excreted into the cavity All of the animals body cells are located near the cavity or slender extensions from it Open systems-not full closed for blood vessels Arthropods and some mollusks Blood and interstitial fluid are the same, together called hemolymph Hemolymph is pumped through open ended vessels into...
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- Summer '08