chapt20 v0106 Circulation

chapt20 v0106 Circulation - Chapter 20: Circulation Blood...

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1 Chapter 20: Circulation Blood Vessels and Hemodynamics
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2 Blood Flow Forms a CLOSED system of tubes that carries blood Most common route heart arteries arterioles capillaries tissue tissue venules veins Flow of oxygenated blood= Arteries (largest) to arterioles to capillaries (smallest) and to the tissue Flow of deoxygenated blood from the tissue- venules (smallest) to veins (largest)
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3 Anastomoses What do you call a prophet's donkey? Anastomoses : A natural communication between two vessels. If the anastomoses provides an alternative route for blood flow this is called Collateral circulation Exercise can increase the body’s creation of collateral circulation, that can prevent tissue necrosis (tissue death)
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4 Arteries Anatomy Artery= (ar= air, ter= to carry)- arteries carry blood that is oxygenated When dissected after death many arteries don’t contain blood. it was thought that they carried air (ar-) The wall of artery has three coats or tunics: 1.) The externa l coat- tunica externa 2.) The m iddle coat- tunica m edia 3.) The interna l coat- tunica interna
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5 Arteries Middle Coat Tunica M edia - thickest layer, smooth Muscle causes the following: 1.) Vasoconstriction - vessels close down, happens with BV trauma to restrict blood flow 2.) Vasodilation - vessels open up, produces warm feeling on skin from exercise
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6 Arteries Inner Coat The interna l coat - tunica interna simple squamous epithelium called: endothelium Endothelium is a continuous layer of cells that line the entire cardiovascular system (heart and BVs) so what’s good for epithelium is good for the heart!
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7 4 Red Vessels 1.) Conducting ( elastic ) arteries – largest Tunica media has lots of elastic fibers, example: the aorta helps propel blood away from the heart pulmonary, aorta and common carotid expand during systole, recoil during diastole; lessens fluctuations in BP 2.) Distributing ( muscular ) arteries medium sized, tunica media has more smooth muscle fibers, they can vasoconstrict and vasodilate, example radial artery 3.) Resistance ( small ) arteries, example: arterioles arterioles control amount of blood to various organs 4.) Metarterioles short vessels connect arterioles to capillaries
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8 Capil laries Capillaries (capillar= hair like)- part of the microcirculation Primary function: exchange nutrients and waste between blood and tissue cells through the interstitial fluid Anatomy of capillary: Single layer of epithelium (endothelium) Metarteriole continues through capillary bed to venule
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9 Capillaries- Red meets Blue
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10 Capillary- Close Up
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11 Veins Venules (=small veins)-When capillaries unite they form these small veins to carry deoxygenated blood V eins - as venules get larger and larger they become veins. Same anatomy as arteries but whimpier but they do differ from arteries because
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chapt20 v0106 Circulation - Chapter 20: Circulation Blood...

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