The Circulatory System: What is the Bloodstream’s Path Through the Heart?

1. The Circulatory System: What is the Bloodstream’s Path Through the Heart? By Carina Lei

2. Functions of the Circulatory System • To transport blood to different organs around your body and back to the heart and lungs • To provide body organs with oxygenated blood • Get rid of harmful products, such as waste or bacteria

3. The Heart The heart is one of the most complex and strongest organs in your body. In fact, the heart is actually a muscle. Make a fist. Your heart is about the size of that. It is located a little to the left of the middle of your chest. Now contract your fist and relax it again. After a while, your hand gets tired. But your heart has to do this over and over, for your whole life! Most human hearts beat around 35 million times each year, and more than 3 ½ trillion times in an average lifetime. This is a picture of the heart.

4. The Path of Blood through the Heart First, the blood enters the right atrium from the superior and inferior Venae Cavae and the coronary sinus. (These veins carry the oxygen-poor blood to the heart) From right atrium, it goes through the tricuspid valve to the right ventricle. (The valves open and close. They are there to stop blood from flowing backwards) From the right ventricle, it goes through the pulmonary semilunar valves to the pulmonary trunk. From the pulmonary trunk, it moves into the right and left pulmonary arteries to the lungs. The lungs give oxygen to the blood, turning the blood cells a bright red. (They are dull red when they are oxygen-poor)

5. The Path of Blood through the Heart From the lungs, oxygenated blood is returned to the heart through the pulmonary veins. From the pulmonary veins, blood flows into the left atrium. From the left atrium, blood flows through the bicuspid (mitral) valve into the left ventricle. From the left ventricle, it goes through the aortic semilunar valves and into the aorta. Blood is distributed to the rest of the body from the aorta. The rest of the body uses up the oxygenated blood and returns it to the heart. The cycle starts all over again.

6. The Path of Blood This picture shows the chambers of the heart and the whether the blood is oxygenated or not. This picture shows the direction of blood flow and also labels the chambers of the heart.

7. Right and Left The blood on the right side of your heart is different from the blood on the left side of your heart. That is why they are separated into two different sides. The blood on the right side of your heart is oxygen-poor, from all the different parts of the rest of the body. After the blood gets oxygenated, the blood cells turn bright red and flow back into your heart- to the left side. The left side pushes the oxygen-rich blood into the aorta, and the aorta transports the blood to all of your different body parts and organs. (Except the lungs) The body parts use up all the oxygen, and the oxygen-poor blood flows back into the left side of your heart. The cycle starts all over again.

8. Diseases Related to the Heart • Rheumatic heart disease Rheumatic Heart Disease- Damage done to the heart’s valves. It is caused by rheumatic fever. • Atherosclerosis- When the walls of your arteries/veins get clogged up with fatty material. It stops the blood flow, which in turn, lead different organs of the body not getting enough oxygen. • Stroke- Stroke happens when the blood supply to your brain is cut off. The vein carrying the blood can either leak, get clogged up, or burst. Part of the brain can get permanently damaged. • Heart Attack- When the heart’s supply of blood is suddenly cut off. Heart attacks aren’t always fatal, but you usually end up with a damaged heart. • High Blood Pressure- When the blood flowing through your veins has excess force. • Lung Cancer- It is caused by smoking. Chemicals and toxins from the smoke go into your lungs, which means the blood that goes to your lungs for oxygen won’t get fresh oxygen. The chemicals and toxins spread throughout the rest of your body, harming other organs.

9. Vocabulary • Atrium- A chamber of the heart that receives blood from the veins and forces it by muscular contraction into a ventricle. • Arteries- blood vessels that carry oxygenated blood away from the heart to the body's cells, tissues, and organs. • Aorta- the main artery of the body, transporting blood out of the heart to the smaller arteries that distribute it to the limbs and all organs except for the lungs. • Capillary- tiny blood vessels that connect the smallest arteries (arterioles) to the smallest veins (venules). • Veins- Blood vessels that return blood from the body tissues to the heart. • Vena Cava- two large veins that carry blood with low levels of oxygen to the right atrium of the heart. • Ventricle- A chamber of the heart that receives blood from one or more atria and pumps it by muscular contraction into the arteries. • Valve- structures that prevent the backward flow of a body fluid, such as blood or lymph.

10. Components of Blood • Red blood cells- Carry oxygen from the lungs to your body’s tissue and take carbon dioxide back to your lungs to be exhaled. • White blood cells- Cells that are part of our immune system. They latch themselves onto bacteria, fungi, and other germs to kill them. • Platelets- Cell fragments in the blood whose main function is to interact with clotting proteins to stop/prevent bleeding. • Plasma- A yellowish fluid that holds all the components.

11. Citations Websites: • http://science.yourdictionary.com/ • http://kidshealth.org/kid/htbw/ • http://anthro.palomar.edu/blood/blood_components.htm • http://www.world-heart-federation.org/cardiovascular-health/heart-disease/different-heart-diseases/ • Google Images Books: • The Heart by Seymour Simon