Nineteen-year-old Antônio is about to take his first plane flight. Shortly after he boards the plane and sits down, a man in his late sixties sits next to him in the aisle seat. About half an hour after the plane takes off, the pilot announces that she is turning the seat belt light off and that “it is now safe to move about the cabin.”
The man in the aisle seat, who has introduced himself to Antônio as Ahaya, immediately unbuckles his seat belt and paces up and down the aisle a few times before returning to his seat. After about forty-five minutes, Ahaya gets up again, walks some more, then sits back down and does some foot and leg exercises. After the third time, Ahaya gets up and paces the aisles, Antônio asks him whether he is walking so much to accumulate steps on a pedometer or fitness tracking device. Ahaya laughs and says no, he is trying to do something even more important for his health—prevent a blood clot from forming in his legs.
Ahaya explains that he has a chronic condition called heart failure. Although it sounds scary, his condition is currently well-managed and he is able to lead a relatively normal lifestyle. However, it does put him at risk of developing other serious health conditions such as deep vein thrombosis (DVT), which is when a blood clot occurs in the deep veins, usually in the legs. Air travel, or other situations where a person has to sit for a long period of time, increases the risk of DVT. Ahaya’s doctor said that he was healthy enough to fly, but that he should walk frequently and do leg exercises to help avoid a blood clot.
As you read this chapter, you will learn about the heart, blood vessels, and blood that make up the cardiovascular system, as well as disorders of the cardiovascular system such as heart failure. At the end of the chapter, you will learn more about why DVT occurs, why Ahaya has to take extra precautions when he flies, and what can be done to lower the risk of DVT and its potentially deadly consequences.
Chapter Overview: Cardiovascular System
In this chapter, you will learn about the cardiovascular system, which transports substances throughout the body. Specifically, you will learn about:
- The major components of the cardiovascular system: the heart, blood vessels, and blood.
- The functions of the cardiovascular system, including transporting needed substances such as oxygen and nutrients to the cells of the body and picking up waste products.
- How blood is oxygenated through the pulmonary circulation, which transports blood between the heart and lungs.
- How blood is circulated throughout the body through the systemic circulation.
- The components of blood, including plasma, red blood cells, white blood cells, and platelets, and their specific functions.
- Types of blood vessels, including arteries, veins, and capillaries, and their functions, similarities, and differences.
- The structure of the heart, how it pumps blood, and how contractions of the heart are controlled.
- What blood pressure is and how it is regulated.
- Blood types: A, B, AB, and O
- Blood disorders, including anemia, HIV, and leukemia.
- Cardiovascular diseases including heart attack, stroke, and angina, and the risk factors and precursors, such as high blood pressure and atherosclerosis, which contribute to them.
As you read the chapter, think about the following questions:
- What is heart failure? How do you think it increases the risk of DVT?
- What is a blood clot? What are the possible health consequences of blood clots?
- Why do you think sitting for long periods of time increases the risk of DVT and why does walking and exercising the legs help reduce this risk?