Chapter 4 is the first of two devoted to the cardiovascular system. This first chapter starts by examining the basic anatomy and physiology of the circulatory system. We then discuss the all-too-common pathology of coronary artery disease and its consequences. Finally, we apply this knowledge as we explore the pharmacological action of the major drug groups used to prevent and to treat coronary artery disease. Chapter 5 , the second on the circulatory system, is devoted to the problem of hypertension (high blood pressure) and the drugs used in its treatment.