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The Cardiovascular System. Blood Vessels. Arteries. Carry blood away from heart High pressure Oxygenated blood (except pulmonary). Angiograms. Angiogenesis and Cancer. VEGF – vascular endothelial growth factor – molecule that signals new blood vessel growth
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The Cardiovascular System Blood Vessels
Arteries • Carry blood away from heart • High pressure • Oxygenated blood (except pulmonary)
Angiogenesis and Cancer • VEGF – vascular endothelial growth factor – molecule that signals new blood vessel growth • Angiogenesis inhibitor medications = anticancer, less blood vessels to “feed” the tumor but with serious side effects – we need angiogenesis for repair.
Narrow lumen Externa: • High pressure = need for thick walls, elastic fibers to be “stretchy” • Smaller arteries are more muscular (and have sphincters) so can contract to close off capillary bed (vasoconstriction)
Capillaries • Huge surface area • Rapid diffusion through single layer of endothelial cells • Each “bed” feeds a small group of cells - no cell in the body is more than 2 cells away from a capillary • Pressure differences cause exchange of O2 and CO2
Size of typical artery or vein = 5mm diameter Size of capillary = 10 µm (0.01mm) diameter = the size on 1 erythrocyte
Veins • Carries blood back to heart • Thinner walls with less muscle • Deoxygenated blood (except for pulmonary • Lower pressure
Why are the valves important in veins, but are not present in arteries?
Spider Veins Reticular Veins
What helps blood move back to the heart besides valves? Why is inactivity a contributing factor for varicose veins?