Blood

Science Connection
Learning About The Cardiovascular System

Designed for Third Grade Students
By Amy L. Miller

Objective:

This activity will succeed in teaching basic concepts of the anatomy, function, and importance of the heart and the circulatory system it controls. A heart rate activity will teach the simple aspects of how our Cardiovascular System works and how the lungs play an important role in this system. To learn the anatomy of the heart, a cow's heart and a pull-apart plastic model heart are utilized. Students will learn the components of blood by doing a hands-on project that will enable them to visualize that our blood is made of many different parts that each have a specific function. At the conclusion of the activity, students will be able to answer the following questions:

1. What is the Cardiovascular System? How did it get its name? What is another name for this system?
2. What happens to our heart rate and breathing when we exercise? Why? How does the function of our lungs impact the workings of our circulatory system?
3. What important role does the heart play in the Circulatory System? How big is your heart? What are the names of the four chambers of the heart?
4. What are the four components of blood and their relative amounts? What is the function of each component?

Lesson:

Pass out copies of the Worksheet to be filled out during the lesson and help the students learn the material. Inform the students that they may use this sheet to complete a future 'quiz' that will show us how much they have learned about the Cardiovascular System. Ask the teacher to give the worksheet as a quiz the week following your presentation and to return them to you so that you can evaluate your effectiveness. It is a good idea to have a crossword puzzle or something else fun on the reverse side to keep them on task when there is down time.

I. Introduction to the Cardiovascular System
Opening Questions:

A. What is the Cardiovascular System? The Cardiovascular System is made up of the heart, blood, and blood vessels. All three of these components work together to transport oxygen and nutrients to the body while aiding the removal of carbon dioxide and other waste products.

B. How did it get its name? Cardio: heart ; vascular: vessels

C. What is another name for this system? Circulatory System

Interesting Fact: If all the blood vessels of the body's Circulatory System were laid end to end, the total length would be more than 60,000 miles!

II. Heart Rate Exercise
Students will take their heart rate. The class will then run in place or do jumping jacks for 30 seconds. Heart rate will be taken a second time. A discussion will be initiated by asking the students the following questions:

A. What happens to our heart rate and breathing when we exercise? Why? (Our heart rate increases and our breathing is more frequent. It is important for this to occur because our body needs more energy when we exercise. We breathe faster so our lungs can take in more oxygen. Our heart pumps faster to transport more oxygen to our muscles so that they can burn the energy faster.)

B. How does the function of our lungs impact the workings of our circulatory system? (The lungs enable us to take in oxygen and remove carbon dioxide.)

Interesting Fact: A mouse's heart rate is over 500 beats per minute, whereas that of an elephant is only 20-30 beats per minute!

III. The Heart
Ask the class the following questions:

A. What important role does the heart play in the Circulatory System? (The heart is a muscle that acts as a pump to circulate blood throughout our body.)

B. How big is your heart? (Your heart is about the size of your fist.)

C. What are the names of the four chambers of the heart? (Right and Left Atria, Right and Left Ventricles. Explain the circulation of blood as a continuous cycle: from the body, through the heart, to the lungs, back through the heart, and out to the body. Draw a diagram on the board. Label the four chambers of the heart and draw arrows that signify the pathway of blood through our bodies.)

Following this, give the students the option of seeing the cow heart or the pull-apart plastic model heart (or both). Hand out one glove to each student who is interested in touching the cow heart. Be sure to point out the shape of the heart and the four chambers they just learned.

Interesting Fact: When you are at rest, your heart pumps an average of 650 liters of blood per hour. The heart is the only muscle in the body that never tires!

IV. What is Blood Made of?
Together, the Science Connector and the students will make 'blood' out of candy. The Science Connector will teach the blood components' names and functions. Following each component introduction, the candy which represents the component will be brought up by students and added to a container. In the end, the mixture should represent a combination of all the components of the blood in their relative amounts. Have the students fill out #4 on their worksheet while you complete this activity.

A. What are the four components of blood and their relative amounts?

B. What is the function of each component?

CANDY RED HOTS 44%: Red Blood Cells (RBCs) - carry oxygen and carbon dioxide around body, RBCs only live for about 3 months but are continuously produced in the bone marrow.
CORN SYRUP 55%: Plasma - syrupy, thick, clear, yellowish liquid that carries dissolved food and wastes.
WHITE JELLY BEANS 1/2%: White Blood Cells (WBCs) - bigger than RBCs, oddly-shaped cells that 'eat' bits of old blood cells and attack germs.
CANDY SPRINKLES 1/2%: Platelets - bits of cells and cytoplasm that help your blood clot.

Emphasize the relative amounts of the blood components. Mix the candy 'blood', dispense into small cups, and pass out one cup to each student. Supply spoons so that the students can eat the candy if they desire.

Interesting fact: There are 5 million red blood cells, 10 thousand white cells and 250 thousand platelets in a pinhead-size drop of blood!

Lesson Prepared by Science Connector Amy L. Miller

Student Worksheets



The University of Arizona
http://student.biology.arizona.edu/sciconn