1. The Circulatory System Blood Heart blood vessels

2. IN: What are four good reasons that blood must be carried to all cells of the body? Why doesn’t a unicellular organism need blood?

3. Function of the circulatory system: CIRCULATE blood throughout the body Transport nutrients to cells Transport wastes away from cells Fight disease Maintain body temperature

4. Three kinds of blood vessels: Arteries –represented by red –Carry blood AWAY from the heart Veins –Represented by blue –Carry blood back to heart Capillaries –Microscopic vessels that join arteries and veins

5. The artery has thick muscular walls so it can Pulsate The vein has valves inside to keep blood flowing toward the heart against gravity

6. Capillaries are only one cell thick. This allows molecules to pass out of the blood to surrounding cells by diffusion while other molecules pass into the blood What is passing out of the red blood cell at X? What may be passing into the blood at Y? What is passing out of the blood’s plasma at Z?

8. How does the circulatory system regulate body temperature and maintain homeostasis?

9. The Heart is a pump It’s made of cardiac muscle tissue with connective tissue and fat tissue on the outside It has four chambers Blood enters form the vena cava, the largest vein Blood leaves through the aorta, the largest artery

10. The heart has four chambers, (chambers are spaces) Two atria- smaller chambers at the top (atrium singular) –They receive blood from veins, pump it to ventricles Two ventricles- larger stronger chambers below –they pump blood out of heart Valves (one way doors) separate the chambers to keep blood flowing the right direction

11. Why is it essential for the mammal heart to have four chambers? (hint- mammals are very active) Frog heart – 3 chambershuman heart – 4 chambers

12. Right side of the heart The atrium receives deoxygenated (oxygen is used up) blood from the body through large veins called the vena cava (superior and inferior) The blood is pumped to the right ventricle, then to the lungs via the pulmonary artery. What happens to blood in the lungs? Rightleft (the heart is facing you)

13. Left side of the heart Oxygenated blood returns to the left atrium from the lungs It’s pumped through a valve to the left ventricle, then to the body via the aorta, or largest artery

14. Coronary circulation The heart is a hard- working muscle It needs a lot of oxygen and nutrients this is supplied by the coronary arteries, and wastes are removed by the coronary veins

15. OUT: Draw red arrows (oxygenated) and blue arrows (deoxygenated) on your heart diagram to show how blood circulates through the heart.