This program takes a close look at the organs of the human circulatory system and how they work to sustain life. After an introductory overview, the composition of blood—its plasma, erythrocytes, leukocytes, and platelets—is analyzed, blood types and Rh factor are considered, the role of hemoglobin in transporting oxygen is explained, and the anatomy and function of the heart is examined. Factors that affect blood pressure and circulation are also discussed, along with the circulatory demands of exercise. A viewable/printable instructor’s guide is available online. A Films for the Humanities & Sciences Production. A part of the series The Human Body: How It Works. (22 minutes)