BSC 2011 Lecture 13: Circulation
5 Oct 2016
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Document Summary
Larger organisms require a circulatory system to carry material to/from cells: consists of. Open circulatory system: arthropods, mollusks, some other invertebrates, heart pumps fluid (hemolymph) through vessels into cavities around organs, lower pressure; less energy required, not in a complete loop. Closed circulatory system: blood vessels form a complete loop. Heart arteries arterioles capillaries. Capillaries venules veins heart. Capillaries are where the material exchange occurs (in 2 sets of capillaries. Blood from the heart can flow through these sequentially or in separate circuits: blood vessels keep circulatory fluid separate from the interstitial fluid, advantages. More efficient delivery of nutrients and o2. Blood flow to specific tissues can be controlled by varying vessel. Blood is a connective tissue diameter: connective tissue- cells that secrete extracellular matrix that they"re suspended in. Produced in bone marrow: erythopoietin- hormone released by kidney in response to insufficient oxygen (hypoxia) controls red blood cell production. Acts on red bone marrow: negative feedback system.
