2. Cardiovascular system Function 1.Transports blood (which contains nutrients, hormones, and gases) 2.Gas Exchange 3.Helps maintain constant body temperature

3. Central Organ The Heart - muscular organ that pumps blood through a network of blood vessels –Myocardium- major portion of the heart –Pericardium- a thick membranous enclosure that protects the heart

4. Heart Anatomy A septum (wall) vertically divides into two sides Right- pumps blood to the lungs Left- pumps blood to the other parts of the body Upper chambers- atrium Lower chambers- ventricles

5. Heart Valves Valves- Flap of tissue that open in only one direction. Valves prevent blood from flowing backwards.

6. Flow of Blood in the Heart Coming from the body, blood is deoxygenated (low O 2, rich in carbon dioxide) enters the: 1. Superior and Inferior Vena Cava 2. Into the Right atrium 3. To the Right Ventricle 4. Through the Pulmonary arteries 5. To the capillaries of the lungs to exchange CO 2 for O 2

7. Flow of Blood in the Heart 6. From the lungs - the blood is rich in O 2 7. Through the pulmonary veins into the Left Atrium 8. To the Left Ventricle 9. Through the Aorta to the rest of the body

9. Blood Vessels Vast network that keep the blood flowing in one direction 1.Arteries and arterioles- carry blood away from the heart. Arteries are large, muscular vessels. They are strong and elastic which allow them to stretch as blood enters from the heart. Arterioles are smaller and less muscular in size and turn into capillaries

10. Blood Vessels 2. Capillaries – tiny blood vessels in networks that allows exchange of material through diffusion, between blood and cells in tissue 3.Veinuoles- small blood vessels that carry deoxygenated blood away from the capillaries. They turn into veins. 4.Veins- large blood vessels that carry deoxygenated blood to the heart. Veins have valves which prevents blood from flowing backwards.

12. Two Cardiovascular Pathways 1.Pulmonary Circulation – blood that travels between the right side of the heart and lungs. Carbon dioxide diffuses out of the capillaries and oxygen diffuses in. 2.Systemic Circulation – oxygenated blood that travels between the left side of the heart and all parts of the body except the lungs.

14. Cardiovascular System End Part 1

15. Cardiovascular System and Heart Health

16. Control of the Heartbeat Muscle cells of the heart contract in waves so that when the first cells are stimulated they in turn stimulate neighboring cells to contract.

17. Phases of the Heartbeat 1. Systole- occurs when the chambers contract 2. Diastole- occurs when the chambers relax Heart Beat - The closing of the two heart valves results in the “lub dub” sound.

18. Pulse Pulse- series of pressure waves within an artery caused by the contractions of the left ventricle. When the ventricles contract, blood surges through the arteries and the elastic walls expand and stretch.

19. Blood Pressure The pressure against a blood vessel wall, usually measured in an artery in the arm systolic pressure: highest pressure during blood ejection from the heart diastolic pressure: lowest pressure when the ventricles relax

20. The End of Part 2