This chapter provides a detailed description of the heart, blood vessels, and blood. It explains how they function together to transport substances throughout the body and maintain homeostasis. The chapter also describes several diseases of the cardiovascular system and lifestyle choices that can help prevent most of them.
- 17.1: Case Study: Your Body's Transportation System
- Nineteen-year-old Antônio is on his first plane flight when his seatmate, 60-year-old Ahaya, begins pacing the aisles and doing leg and foot exercises at regular intervals. Ahaya explains that he has chronic heart failure, which, although well-managed, puts him at greater risk for certain complications of flying, like deep vein thrombosis (DVT). In this chapter, you will learn about the heart, blood vessels, and blood that make up the cardiovascular system, as well as its potential disorders.
- 17.2: Introduction to the Cardiovascular System
- The cardiovascular system, also called the circulatory system, is the organ system that transports materials to and from all the cells of the body. The materials carried by the cardiovascular system include oxygen from the lungs, nutrients from the digestive system, hormones from glands of the endocrine system, and waste materials from cells throughout the body. Transport of these and many other materials is necessary to maintain homeostasis of the body.
- 17.3: Heart
- The heart is a muscular organ behind the sternum (breastbone), slightly to the left of the center of the chest. A normal adult heart is about the size of a fist. The function of the heart is to pump blood through blood vessels of the cardiovascular system. The continuous flow of blood through the system is necessary to provide all the cells of the body with oxygen and nutrients and to remove their metabolic wastes.
- 17.4: Blood Vessels
- Blood vessels are the part of the cardiovascular system that transports blood throughout the human body. There are three major types of blood vessels. Besides veins, they include arteries and capillaries.
- 17.5: Blood
- Blood is a fluid connective tissue that circulates throughout the body through blood vessels of the cardiovascular system. What makes blood so special that it features in widespread myths? Although blood accounts for less than 10 percent of human body weight, it is quite literally the elixir of life. As blood travels through the vessels of the cardiovascular system, it delivers vital substances such as nutrients and oxygen to all of the cells and carries away their metabolic wastes.
- 17.6: Blood Types
- Blood type (or blood group) is a genetic characteristic associated with the presence or absence of certain molecules, called antigens, on the surface of red blood cells. These molecules may help maintain the integrity of the cell membrane, act as receptors, or have other biological functions. A blood group system refers to all of the gene(s), alleles, and possible genotypes and phenotypes that exist for a particular set of blood type antigens.
- 17.7: Cardiovascular Disease
- Cardiovascular disease is a class of diseases that involve the cardiovascular system. They include diseases of the coronary arteries that supply the heart muscle with oxygen and nutrients; diseases of arteries such as the carotid artery that provide blood flow to the brain; and diseases of the peripheral arteries that carry blood throughout the body. Worldwide, cardiovascular disease is the leading cause of death, causing about a third of all deaths each year.
- 17.8: Case Study Conclusion: Flight and Chapter Summary
- At the beginning of this chapter, you learned about Antônio and Ahaya, who met while sitting next to each other on a plane. During the flight, Ahaya got up to take frequent walks and was doing leg exercises to try to avoid the medical condition DVT. DVT occurs when a blood clot forms in a deep vein, usually in the leg. It can be very dangerous—even deadly.
Thumbnail: Flow of blood through the cardiac chambers. (Public Domain; Josinho8).