This edition: Circulation: A River of Life
To sustain life in complex organisms, food and chemical products and by-products must be moved rapidly to and from the body’s living cells. In animals, the transport medium is blood moving through the circulatory system. The program cuts to a hospital emergency room as a trauma unit stabilizes a patient. The ER doctor narrates the scene and details the composition of circulatory systems that occupy most animals: the heart, blood, and a closed system of vessels, veins, and capillaries. Striking animation illustrates the typical circulatory system.
Interestingly, different animals have different types of hearts that are designed for their particular survival needs. This is the topic of the second segment, in which Dr. James Hicks discusses his study of alligator hearts and the reptilian ability to hold more oxygen in their blood. Lastly, a case study of a heart attack victim is the context for an exploration of disorders of the cardiovascular system. The basic structure and function of the heart, the primary component of the circulatory system, are detailed by Dr. Shahbudin Rahimtoola. He explains the heart’s crucial timing mechanism and how the two coronary arteries branch off the aorta to cycle blood throughout the system.