1. Performing Tonight: Your Body The Circulatory System

2. Starring: YOUR BLOOD! Blood is something we cannot live without. Blood gives us: Oxygen and nutrients Oxygen and nutrients A way to keep warm A way to keep warm and cool and cool A way to fight infections A way to fight infections A way to get rid of A way to get rid of waste products

3. Where does it all come from? Blood is made in your bone marrow. This soft tissue, found in our bones, constantly works to make the blood! Bone marrow is especially active in the vertebrae, ribs, pelvis, skull, and sternum. Why do you think that is?

4. Bone marrow makes three different parts of your blood. The cells made in the bone marrow travel in plasma, a yellowish fluid that is 90% water and contains nutrients, hormones, and waste products. Blood is a mixture of plasma and blood cells.

5. Getting to Know Your Blood: Red Blood Cells You can recognize red blood cells by their shape: they look like indented, flattened discs! The RBC give the blood its red color when hemoglobin, a protein in the blood, releases oxygen into tissues. There are more RBC in the body than any other cell type! Each RBC has the life span of about 4 months. New RBC are made daily.

6. Defend Yourself: White Blood Cells to the Rescue! White blood cells are essential in defending your body from infection. WBC move in and out of the bloodstream to reach infected tissues. When you are sick, your body builds up the WBC to fight off the infection. Some WBC “remember” how to fight germs so that they can quickly attack them in the future. There are several types of WBC in the body. Their life span can last a few days to a few months.

7. Can you clot it? Platelets can! The tiny, oval shaped cells in blood are called platelets. They help clot your blood when a blood vessel breaks. Platelets will gather in a certain area to seal off the leak. Proteins with clotting factors helps the platelets form solid lumps to stop blood flow. Platelets survive only about 9 days! When large blood vessels are cut, sometimes platelets need some help. That’s when we get stitches! In one cubic cm of blood, there are about 250,000 to 450,000 platelets.

8. There are two types of blood vessels in your body because there are two types of blood. Veins – Carry blood that needs oxygen Arteries – Carry blood that has oxygen In pictures, veins are usually blue. Why? In pictures, arteries are usually red. Why? Veins or Arteries? How can you tell?

12. Veins Veins carry the blood to the heart. The smallest veins, also called venules, are very thin. They join larger veins that open into the heart. The veins carry dark red blood that doesn't have much oxygen. Veins have thin walls. They don't need to be as strong as the arteries because as blood is returned to the heart, it is under less pressure. Veins carry the blood to the heart. The smallest veins, also called venules, are very thin. They join larger veins that open into the heart. The veins carry dark red blood that doesn't have much oxygen. Veins have thin walls. They don't need to be as strong as the arteries because as blood is returned to the heart, it is under less pressure.

13. Arteries Arteries are tough, elastic tubes that carry blood away from the heart. As the arteries move away from the heart, they divide into smaller vessels. The largest arteries are about as thick as a thumb. The smallest arteries are thinner than hair. These thinner arteries are called arterioles. Arteries carry bright red blood! The color comes from the oxyegen that it carries. Arteries are tough, elastic tubes that carry blood away from the heart. As the arteries move away from the heart, they divide into smaller vessels. The largest arteries are about as thick as a thumb. The smallest arteries are thinner than hair. These thinner arteries are called arterioles. Arteries carry bright red blood! The color comes from the oxyegen that it carries.