2. CIRCULATORY SYSTEM The highway system of the body

3. Why Have One? Small organisms with few cells don’t need one because….. 1. Most cells are in contact with their environment so…. oxygen, nutrients, and waste can easily diffuse across the cell membrane

4. Larger organisms must have a circulatory system because…. their cells are NOT in contact with the environment substances made in one part of the body need to be transported to another part

5. FUNCTION Transport oxygen to cells nutrients to cells carbon dioxide away from cells wastes away from cells

6. TYPES 1. Open: blood leaves vessels and goes into tissues and surrounds cells Ex: grasshopper 2.Closed: blood is completely contained in vessels Ex: human

7. PARTS 1. Heart = pump 2. Blood vessels = tubes 3. Blood = liquid tissue

8. HEART »Two pumps side by side »Has four chambers »Two pumps side by side »Has four chambers

9. HEART PARTS Pericardium: protective sac that surrounds the heart Atria: upper chambers, thin walled Ventricles: lower chambers, thick walled

10. Valves: flaps of tissue between chambers Prevent backflow of blood - keeps blood moving in one direction Septum: thick, muscular wall that divides the heart in half

11. Heart Diagram 1. Aorta: largest artery of the body - carries blood away from heart to the body 2. Pulmonary Arteries: carry blood to the lungs 3. Left Atrium: contraction sends blood to left ventricle 1. Aorta: largest artery of the body - carries blood away from heart to the body 2. Pulmonary Arteries: carry blood to the lungs 3. Left Atrium: contraction sends blood to left ventricle

12. 4. Pulmonary Vein: bring blood from the lungs into the heart 5. Mitral Valve 6. Valve 7. Left Ventricle: sends blood out through aorta to the rest of the body 4. Pulmonary Vein: bring blood from the lungs into the heart 5. Mitral Valve 6. Valve 7. Left Ventricle: sends blood out through aorta to the rest of the body

13. 8. Septum: wall 9. Right Ventricle: sends blood out through pulmonary arteries to lungs 10. Inferior Vena Cava: brings blood from lower parts of body into heart 11. Tricuspid Valve 8. Septum: wall 9. Right Ventricle: sends blood out through pulmonary arteries to lungs 10. Inferior Vena Cava: brings blood from lower parts of body into heart 11. Tricuspid Valve

14. 12. Right Atrium: receives blood from all parts of the body except lungs 13. Pulmonary Veins 14. Pulmonary Arteries 15. Superior Vena Cava: brings blood from the upper parts of the body to the heart 12. Right Atrium: receives blood from all parts of the body except lungs 13. Pulmonary Veins 14. Pulmonary Arteries 15. Superior Vena Cava: brings blood from the upper parts of the body to the heart

15. CIRCULATION Pulmonary Right side of the heart pumps oxygen poor blood from the heart to the lungs Pulmonary Right side of the heart pumps oxygen poor blood from the heart to the lungs

16. CIRCULATION Systemic Oxygen rich blood comes back to the left side of the heart Blood is pumped out to the cells of the body Systemic Oxygen rich blood comes back to the left side of the heart Blood is pumped out to the cells of the body

17. PATHWAY Right atrium -> Right ventricle -> Pulmonary artery -> Lungs -> Pulmonary vein -> Left atrium -> Left ventricle -> Aorta -> Arteries, capillaries, veins -> Vena cava -> right atrium Right atrium -> Right ventricle -> Pulmonary artery -> Lungs -> Pulmonary vein -> Left atrium -> Left ventricle -> Aorta -> Arteries, capillaries, veins -> Vena cava -> right atrium