Anatomy and Physiology: Cardiovascular and Lymphatic Circulation
Cardiovascular and Lymphatic Circulation
We can't possibly look at all 12,000 miles (about 19,300 km) of blood vessels, so I had better find an easy way for you to navigate your way around the vascular part of the cardiovascular system! In The Heart, you learned that in the course of about a minute, all of your blood could make one full circulation around the body.
Before you start telling everyone that your blood travels at 720,000 mph (1,158,000 kph), don't forget that none of the blood travels through all of the vessels in one minute! As you saw in The Blood, arteries split into arterioles, arterioles split into capillaries, capillaries merge into venules, and venules merge into veins. The maximum journey for any one blood cell is therefore much shorter, on the order of yards or meters.
In this section, you'll learn what makes the vessels different, not to mention some surprising quirks in both cardiovascular and lymphatic circulation. The unique life of a fetus, as you shall see requires some differences in the circulation, especially with that weird-looking umbilical cord. I'll also discuss what blood pressure is, and how to measure it.
Excerpted from The Complete Idiot's Guide to Anatomy and Physiology © 2004 by Michael J. Vieira Lazaroff. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.