Download Blood Vessels

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 (left) are thicker than that of veins (right)
 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
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings