Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Tidbits  your blood vessels are hollow tubes that circulate your blood  If you took all of the blood vessels out of an average child, and laid them out in one line, the line would be over 60,000 miles long!  An adult's vessels would be closer to 100,000 miles long!

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 3 Types of Blood Vessels 1.Arteries 2.Veins 3.Capillaries

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 1. Arteries  Carry blood away from the heart  Carry oxygenated blood with one exception

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Arteries  The walls of arteries (a) are thicker than that of veins (b)  Arteries are tough on the outside and smooth on the inside.  An artery actually has three layers:  outer layer of tissue  muscular middle (elasticity helps move blood along)  inner layer of epithelial cells

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Movement of Blood Through Arteries  Arteries are located deep near the bones (with a few exceptions)  Arterial blood is pumped by the heart under high pressure  Pulse (= heart rate)  The contraction of the artery keeps pace with the beat of the heart.  Blood pressure  blood flowing through the arteries because it has a higher pressure than the blood in the veins  uses two numbers. systole diastole The walls of arteries are thicker than that of veins

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Major Arteries of Circulation  Aorta  Largest artery in the body  Leaves from the left ventricle of the heart  Regions  Ascending aorta  Aortic arch  Thoracic aorta  Abdominal aorta —passes through the diaphragm into the abdominopelvic cavity

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Vessels of the Aortic Arch  Brachiocephalic  Left common carotid  Left subclavian

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Arterial Supply of the Brain  Internal carotid arteries divide into  Anterior and middle cerebral arteries  These arteries supply most of the cerebrum

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 2. Capillaries  walls are only one cell layer thick  some allow for only one RBC to pass at a time  allow for exchanges between blood and tissue

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Veins  Carry blood to the heart  Carry deoxygenated blood (with one exception)  The walls of veins are thinner, however the lumen is larger  Veins are more superficial near the skin (with a few exceptions)  Veins are under low pressure

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Movement of Blood Through Veins  Larger veins have valves to prevent backflow  Veins use the “milking” action of muscles to help move blood

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Major Veins of Circulation  Vena Cava  Largest vein in the body  Returns blood to the right atrium  Regions  Superior vena cava drains the head and arms  Inferior vena cava drains the lower body