2.3 The Circulatory and Respiratory Systems The circulatory system consists of the heart, arteries, capillaries, and veins. Your heart is a pump that pushes approximately 4 L of blood through your body every minute. The main purpose of the respiratory system is to exchange gases. The main organ of the respiratory system are the lungs. See pages 82 - 83 (c) McGraw Hill Ryerson 2007

Taking a Closer Look at the Heart The heart pumps blood throughout the body. The heart has four chambers: Left atrium Blood arrives from your lungs Right atrium Blood arrives from your body Left ventricle Pumps blood to your body Right ventricle Pumps blood to your lungs Between each of these chambers is a valve. See page 84 (c) McGraw Hill Ryerson 2007

The Circulatory System The circulatory system moves blood throughout the body. There are three types of blood vessels: Arteries Carry oxygenated blood away from your heart Capillaries are tiny blood vessels Responsible for transfer of oxygen and nutrients into the body cells and collecting waste from the cells. Veins Blood containing waste products returning to the heart. See pages 85 - 86 (c) McGraw Hill Ryerson 2007

The Circulatory System Starting with the right atrium, try placing the following structures in the correct order that blood flows through the body. Left ventricle Body Right atrium Left atrium Lungs Right ventricle See pages 87 - 88 (c) McGraw Hill Ryerson 2007

The Components of Blood About 55% of blood is a liquid called plasma. Contains proteins, minerals, and other substances. Red blood cells carry oxygen from the lungs to the cells. White blood cells fight infection. Platelets are important for clotting blood. See pages 88 -89 (c) McGraw Hill Ryerson 2007

The Respiratory System The respiratory system moves oxygen into your body and carbon dioxide out of your body. When you inhale, air is filtered by tiny hairs called cilia. Air passes through your larynx and continues down your trachea towards your lungs. At the base of the trachea are two tubes called bronchi. Bronchi branch into smaller air tubes called bronchioles. See page 90 (c) McGraw Hill Ryerson 2007

Gas Exchange in the Alveoli There are millions of alveoli at the ends of the bronchioles, and this is where gas exchange takes place. Oxygen and carbon dioxide move back and forth between the alveoli and the surrounding blood vessels. See page 91 (c) McGraw Hill Ryerson 2007

Smoking Smoking may cause both respiratory disease and heart disease. Respiratory diseases could include emphysema and lung cancer. Emphysema causes the alveoli walls to lose their elasticity. This may make breathing very difficult. Smoking also destroys the cilia lining your respiratory system. Take the Section 2.3 Quiz See page 92 (c) McGraw Hill Ryerson 2007