The Heart and Circulatory System Copyright 2010. PEER.tamu.edu What are some of the things that a heart symbolizes? Health Love Cupid Concern Romance Passion What is the real purpose of the heart? Functions of the Circulatory System A cell needs oxygen and nutrients. • Deliver nutrients and oxygen to body cells. • Carry carbon dioxide and other waste products away from the body cells. A cell needs to get rid of carbon dioxide and other wastes. Organs of the Circulatory System • Heart: A muscle that pumps blood to all parts of the body. – The human heart is made of four chambers. The right atrium, right ventricle, left atrium and left ventricle. – Valves are flaps of tissue that open & close to let blood in & out of the parts of the heart. Fun Fact! •Your heart beats with about the same strength it takes to squeeze a tennis ball. •Squeeze a tennis ball and see how hard that is. • Now think what it must be like for your heart to do this 70 times a minute, 60 minutes an hour, 24 hours a day - for a lifetime! Do all animals’ hearts have 4 chambers? Look at the four chambers of the heart: Question: Why is the right labeled left and the left labeled right? Answer: Anatomy drawings are labeled as if they were in a person or animal that is facing you! This is a sheep’s heart that has been dissected, or opened. Locate the four chambers of the heart. The stringy structures in the heart are the valves that open and close to let blood move between the chambers of the heart. Stop and Think: • What are some things that could make your heart beat faster? • What are some things that could make your heart beat slower? Blood Vessels • Arteries are pipelines that generally carry blood away from the heart. They carry oxygen-rich blood. They are usually designated by the color red because oxygen-rich blood is red. • Veins generally carry oxygen-poor blood back to the heart from the rest of the body. They are usually designated by the color blue because oxygen-poor blood is a darker color. Your arteries and veins run to every location in your body in a determined path. Why do you think some people compare our circulatory system to a network of roads? Blood Vessels • Capillaries are microscopic blood vessels that connect arteries to veins. • The Capillaries are in between the artery on the left and the vein on the right They are where oxygen & waste exchange occur. • They are only big enough for one blood cell to pass at a time. Click here for a video of blood flowing in the blood vessels The little donut-shaped red blood cell (scientific name erythrocyte) squeezes through the capillary and drops off its cargo of nutrients and oxygen Circulation • This is the path of the blood through the heart, lungs, and body. Click here for a silly circulation song! Follow the arrows in the pictures to trace the flow of blood through the heart, lungs and body. Now discuss these review questions: • What are the functions of the circulatory system? • What are the major organs of the circulatory system? • What are the main parts of the heart? • What do arteries and veins do? • How big are capillaries? • What path does blood take as it goes through your body? • A thinking question: Do you think all living things have a heart?