Tidbits your blood vessels are hollow tubes that

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

1. Arteries § Carry blood away from the heart § Carry oxygenated blood with

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 https: //www. youtube. com/watch? v=fqbj. In. QJtz. U § 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 https: //www. youtube. com/watch? v=wu 01 vlf 4 ORM § 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 https: //commons. wikimedia. org/wiki/File: Venous_valv e_00013. gif 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 Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings