Blood Vessels http://www.majordifferences.com/2013/02/difference-between-artery-and-vein.html#.WiSD2VVKt0w ateries veins • Carry blood away from the • Carry blood toward the heart heart • Elastic arteries resist • Low pressure pressure and even it out • Thin walls (partially) • Large lumen • Muscular arteries maintain • Valves to prevent backflow & control pressure and promote flow of blood • Arterioles control blood in only one direction flow into capillaries capillaries – only endothelium http://anatomybody101.com/the-heart-is-made-of-what- muscle/the-heart-is-made-of-what-muscle-blood-vessels- tunica-intima-endothelium-subendothelial-layer-internal-or- external-elastic-membrane-tunica-media-externa-basement- membrane-artery-vein-capillary-bed/ muscular artery – vein – nerve elastin stain http://zoomify.lumc.edu/histonew/cardiovascular/dms108/popup.html Diagram of the tunics of an arterial wall (above): On the left, the drawing illustrates a typical stain and the tunica media smooth muscle are apparent; on the right, the same arterial wall has been stained with a special stain for elastin and you can see the elastin fibers running between the smooth muscle cells of the tunica media as well as through the loose connective tissue of the tunica externa. http://www.apsubiology.org/anatomy/2020/2020_Exam_Reviews/Exa m_1/CH19_Vessel_Wall_Histology.htm Elastic artery – stained for elastin https://casweb.ou.edu/p bell/Histology/Caption s/Cardiovascular/46.ela stic.art.10x.html Capillaries come in 3 varieties – most are “continuous” though http://ib.bioninja.com.au/standard-level/topic-6-human-physiology/62-the-blood-system/capillaries.html Major Circulatory Routes • Pulmonary circulation • Systemic circulation [includes] • Cardiac circulation • Cerebral circulation – really to the whole brain • Hepatic portal system • Note that there are other portal systems as well • Fetal circulation Circle of Willis – more details … and the details go on … http://www.proprofs.com/flashcards/story.php?title=neurology-circle-willis Hepatic portal drainage note that input comes from - celiac trunk - superior mesenteric artery - inferior mesenteric artery http://humananatomylibrary.com/hepatic-portal-vein-anatomy/hepatic-portal-vein-anatomy-anatomy-of-the-hepatic-portal-system-human-anatomy-diagram/ Fetal Circulation Note especially the ductus venosus http://what-when-how.com/nursing/normal-pregnancy- maternal-and-newborn-nursing-part-2/ Fetal Circulation http://www.studyblue.com/notes/note/n/antphy-2201-study- guide-2010-11-maddux/deck/9736669.