Blood Vessel Outline - The Cardiovascular System: Blood...

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The Cardiovascular System: Blood Vessels and Hemodynamics Structure and function of blood vessels Hemodynamics Major circulatory routes Anatomy of Blood Vessels Closed system of tubes that carries blood Arteries carry blood from heart to tissues Capillaries are thin enough to allow exchange Venules merge to form veins that bring blood back to the heart Vasa vasorum Arteries Tunica interna (intima) Tunica media Tunica externa Sympathetic Innervation Vascular smooth muscle is innervated by sympathetic nervous system increase in stimulation causes muscle contraction or vasoconstriction injury to artery or arteriole causes muscle contraction reducing blood loss (vasospasm) decrease in stimulation or presence of certain chemicals causes vasodilation Elastic Arteries
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Largest-diameter arteries have lot of elastic fibers in tunica media Muscular Arteries Medium-sized arteries with more muscle than elastic fibers in tunica media Arterioles Small arteries delivering blood to capillaries Metarterioles form branches into capillary bed to bypass capillary bed, precapillary sphincters close & blood flows out of bed in thoroughfare channel Capillaries form Microcirculation Microscopic vessels that connect arterioles to venules Found near every cell in the body but more extensive in highly active tissue Structure is single layer of simple squamous epithelium and its basement membrane Types of Capillaries Continuous capillaries Fenestrated capillaries Sinusoids Venules Small veins collecting blood from capillaries Venules that approach size of veins more closely resemble structure of vein
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Veins Proportionally thinner walls than same diameter artery Valves are thin folds of tunica interna designed to prevent backflow Venous sinus has no muscle at all Anastomoses Union of 2 or more arteries supplying the same body region blockage of only one pathway has no effect Alternate route of blood flow through an anastomosis is known as collateral circulation Alternate routes to a region can also be supplied by nonanastomosing vessels Systemic Circulation All systemic arteries branch from the aorta All systemic veins drain into the superior or inferior vena cava or coronary sinus to return to the right-side of heart Circulatory Routes Hepatic Portal circulation is capillaries of GI tract to capillaries in liver Arterial Branches of Systemic Circulation
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All are branches from aorta supplying arms, head, lower limbs and all viscera
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This note was uploaded on 08/20/2008 for the course V SC 400B taught by Professor Marchello during the Spring '08 term at University of Arizona- Tucson.

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Blood Vessel Outline - The Cardiovascular System: Blood...

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