The circulatory system consists of the heart, blood vessels, and blood, which circulates throughout the entire body. The heart is a muscle that pumps blood through arteries to deliver oxygen and nutrients to the body and returns deoxygenated blood to the heart through veins to be re-oxygenated. Red blood cells carry oxygen from the lungs to tissues and carbon dioxide back to the lungs, while white blood cells help fight infection and platelets help stop bleeding.

1. Circulatory System - is a system of organs that includes the heart, blood vessels, and blood which is
circulated throughout the entire body of a human.
Heart - It's the muscle at the center of your circulation system, pumping blood around your body as your
heart beats. This blood sends oxygen and nutrients to all parts of your body, and carries away unwanted
carbon dioxide and waste products.
Artery - Arteries distribute oxygen-rich blood to your body. Arteries, part of your circulatory
(cardiovascular) system, are the blood vessels that bring oxygen-rich blood from your heart to all of your
body's cells. They play a crucial role in distributing oxygen, nutrients and hormones throughout your
body.
Capillary - The primary function of capillaries is the exchange of materials between the blood and tissue
cells.
Vein - Veins have one-way valves instead of muscles, to stop blood from running back the wrong way.
Generally, veins carry deoxygenated blood from the body to the heart, where it can be sent to the lungs.
Red blood cells - Red blood cells carry oxygen from our lungs to the rest of our bodies. Then they make
the return trip, taking carbon dioxide back to our lungs to be exhaled.
White blood cells - White blood cells are part of the body's immune system. They help the body fight
infection and other diseases.
Platelets - Platelets, or thrombocytes, are small, colorless cell fragments in our blood that form clots and
stop or prevent bleeding. Platelets are made in our bone marrow, the sponge-like tissue inside our
bones.

4. • Activity 2: Pump It Up
In this activity, you will be creating the heart model to describe how the
heart pumps blood.
Materials Needed:
 1 small jar
 1 balloon
 2 pieces flexible drinking straws
 Tape or glue
 1 pair of scissors
 1 large pan
 Water, toothpick
• Procedures:
1. Fill the jar half full of water.
2. Cut the neck of the balloon off at the part where it starts to widen into a
balloon. Set the neck part aside.
3. Stretch the balloon over the opening of the jar, pulling it down as tightly
as you can. The flatter you can get the surface of the balloon, the better.
4. Get a sharp toothpick and gently poke two small holes on the surface of
the balloon. Make them about an inch apart from each other and near
opposite edges of the jar.
5. Get your straws and push one through each hole with the bendy part
sticking out of the top. The straws should fit securely in the holes so that
no air can get through around the straws.
6. Slide the uncut end of the balloon neck onto one of the straws and tape it
around the straw.
7. Set your pump in a large pan or the sink to catch the pumped water.
Bend the straws downward. Gently press in the center of the stretched
balloon and watch what happens to the water in the jar.

5. Guide Questions:
1. What does the water inside the jar represent?
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2. What happens to the water inside the jar as you press the center of the
stretched balloon?
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3. How is heart pump model similar to the human heart?
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4. Is it important for the human heart to pump? Why?
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