The Circulatory System

1. The Circulatory System

2. The Cardiovascular System • Every part of your body needs to have access to blood • Blood is the bodies way of spreading out things like oxygen, energy and food • Those nutrients have to reach all of the cells in the body

3. The Cardiovascular System • The cardiovascular system is made up of the blood, heart and blood vessels • It is a system that has to be constantly working in order for a person to live • The cardiovascular system never gets a rest

4. The Heart • The main organ that circulates blood around the body is the heart • The heart is a four chambered organ that uses two chambers to force blood to the lungs and two chambers to force blood to the rest of the body

5. The Heart • When looking at a heart you can tell that not all four chambers are the same • Each side of the heart is divided to an upper and lower part • The atriums are the blood collecting chambers in the heart • The ventricles are the blood pumping chambers in the heart

6. The Heart • The heart is divided by the septum • This is a wall of muscle that separates the atriums and ventricles • Valves are flaps of tissue that separate the sections of the heart • These flaps prevent the different sections of blood from mixing

7. How the Heart Pumps • The heart has to have a very systematic pattern for how it beats • This keeps the blood flow to the body regular and constant • There are a few steps to the heart pumping

8. How the Heart Pumps • It is important to remember that when the heart pumps it has two different stages • First the atriums contract together • After they contract the ventricles contract together • This gives a heart beat a distinct “lub – dup” sound

9. Path of Blood • 1. Deoxygenated (DOX) blood enters the heart through the right atrium • This is the main collecting chamber from the body • 2. The DOX blood is forced into the right ventricle when the atriums contract

10. Path of Blood • 3. The ventricles contract and send the blood to the lungs • After the blood returns from the lungs it is oxygenated (OX) • 4. The OX blood from the lungs then collects in the left atrium

11. Path of Blood • 5. The atriums pump and send blood down to the left ventricle • The left ventricle is the strongest part of the heart • 6. The ventricles then pump. This sends blood to the various parts of the body

12. Electrical Systems • The heartbeat is controlled by electrical systems • The heart only beats when there is an electrical current that tells it how and why to beat • When this electrical impulse is moving and regular, people have a normal heartbeat

13. Electrical Systems • The SA node is a group of cells on the right atrium that initiate their own electrical signal • This signal regulates the heartbeat • It also tells the atriums to contract • When this group of cells does not work correctly, a pacemaker is installed

14. Electrical Systems • The AV node is located in the septum and collects signals from the SA node • This tells the ventricles when to contract • This grouping of cells is reactive and relies on the information that is passes on to it from the SA node

15. http://www.youtube.com/watch?v=H04d3rJCLCE

16. Blood Vessels • The circulatory system is known as a closed system • This means that the circulatory system is contained at all times • Blood is kept within the heart or blood vessels • The only time this changes is if there is an injury

17. Blood Vessels • Arteries are blood vessels that carry blood away from the heart • Arteries often carry oxygenated blood from the heart to the cells that are going to use it • The only exception is the artery that carries blood from the heart to the lungs

18. Blood Vessels • Veins are blood vessels that carry blood to the heart • Veins often carry blood that has little oxygen from the body to the heart • The only exception is the vein that carries oxygenated blood from the lungs to the heart

19. Major Blood Vessels • The major artery in the body is the aorta • This is the artery that carries blood from the heart to the rest of the body • The femoral artery carries blood to the legs • The carotid artery carries blood to the brain • The brachial artery carries blood to the arms

20. Major Blood Vessels • The vena cava is the major vein that feeds the heart • It has two parts that meet at the heart • One collects blood from the upper part of the body and one collects blood from the lower part of the body

21. Capillaries • As the blood vessels divide they get smaller an smaller • The smallest type of blood vessels are capillaries • Capillaries are blood vessels that are so thin that only single blood cells can move through them

22. Capillaries • The network of capillaries is so extensive in the body that each cell in the body is no further than one cell away from a capillary • This is how blood can diffuse materials to all the different cells in the body