Ch. 42 Circulation

Ch. 42 Circulation - Animal Circulation Chapter 42 BIOL 112...

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Circulation 1 BIOL 112 Animal Circulation Chapter 42 BIOL 112 BIOL 112 Circulation and Circulatory Systems Major function: transport of materials throughout body Direct interaction with most other organ systems “Services:” z Gas Exchange Transports gasses exchanged for respiration: CO 2 ; O 2 z Nutrients Materials picked up by digestive system are distributed throughout body z Wastes Products to be removed by excretory system z Hormones Communication and control throughout body z Body Defenses Inflammatory/Immune Systems BIOL 112 Types of Circulatory Systems Primitive z No circulation: protozoa, cnidarians, flatworms z Simple circulation: nematodes use pseudocoelom Advanced — full organ system to perform z Open Circulation — arthropods, molluscs. Blood is not completely enclosed in vessels throughout circuit to/from heart. Blood empties into sacs called sinuses which surround many major organs z Closed Circulation — annelids, chordates. Blood is contained entirely in vessels in circuit to/from heart. Regarded as more efficient because higher blood pressure is maintained in circuit BIOL 112 BIOL 112
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Circulation 2 BIOL 112 BIOL 112 BIOL 112 BIOL 112 Evolutionary Progression in Vertebrate Circulation Single Circulation Heart has two chambers: 1 atrium; 1 ventricle (fish) Double Circulation Separation of circulation to gas exchange surfaces from circulation to rest of body z Amphibia Heart has 3 chambers: 2 atria; 1 ventricle z Reptiles Beginnings of separation of lung (pulmonary) from body (systemic) circulation routes. Transition from 3 chambers to 4: appearance of septum between halves of ventricle z Birds; Mammals Full separation of pulmonary from systemic circulation. Heart has 4 chambers: 2 atria; 2 ventricles Blood must shunt through pulmonary system before it can enter systemic circulation; each half of the heart (1 atrium; 1 ventricle) involved uniquely with one part of total circulation BIOL 112 Two-chambered heart Three-chambered heart Four-chambered heart BIOL 112
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Circulation 3 BIOL 112 BIOL 112 BIOL 112 Components of Circulation System For closed circulatory system BIOL 112 BIOL 112 The Heart as Pump Human heart: right/left atrium; right/left ventricle Between each atrium and ventricle: valves; permit one-way flow of blood from each atrium into each ventricle only Atrioventricular Valves z Left Mitral Valve z Right Tricuspid Valve Between each ventricle and blood vessels carrying blood away from heart: valves Semilunar Valves Heartbeat: “thub-lub” z Thub AV valves snap shut after atria contract z Lub Semilunar valves snap shut after ventricles contract BIOL 112
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Circulation 4 BIOL 112 BIOL 112 Blood Vessels as Tubes Artery Multilayered tube: (lumen), endothelium, smooth muscles, connective tissue, epithelium Vein Multilayered tube: (lumen), endothelium, smooth muscles, connective tissue, epithelium Distinguish arteries and veins z Structural Artery walls thicker, with more muscle than vein; veins have valves, arteries do not
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This note was uploaded on 04/28/2010 for the course BIOL 102 taught by Professor Aufderheide during the Spring '10 term at Texas A&M.

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Ch. 42 Circulation - Animal Circulation Chapter 42 BIOL 112...

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