The Heart and Circulatory System

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What are some of the things that a heart symbolizes?

Love

Passion

Health

Concern

Romance

Cupid

What is the real purpose of the heart?

Functions of the Circulatory Functions of the Circulatory SystemSystem

• Deliver nutrientsnutrients and oxygenoxygen to body cells.

• Carry carboncarbon dioxidedioxide and other waste products away from the body cells.

A cell needs oxygenand nutrients.

A cell needs to get rid of carbon dioxideand other wastes.

Organs of the Circulatory System

• Heart: A muscle that pumps blood to all parts of the body.

– The human heart is made of four chambers. The right atrium, right ventricle, left atrium and left ventricle.

– Valves are flaps of tissue that open & close to let blood in & out of the parts of the heart.

Fun Fact!•Your heart beats with about the same strength it takes to squeeze a tennis ball.

•Squeeze a tennis ball and see how hard that is. 

• Now think what it must be like for your heart to do this 70 times a minute, 60 minutes an hour, 24 hours a day - for a lifetime!

Do all animals’ hearts have 4 chambers?

Look at the four chambers of the heart:Look at the four chambers of the heart:

Question: Why is the right labeled left and the left labeled right?

Answer: Anatomy drawings are labeled as if they were in a person or animal that is facing you!

This is a sheep’s heart that has been dissected, or opened. Locate the four chambers of the heart. The

stringy structures in the heart are the valves that open and close to let blood move between the chambers of

the heart.

• What are some things that could make your heart beat faster?

• What are some things that could make your heart beat slower?

Stop and Think:

Blood Vessels• ArteriesArteries are pipelines that

generally carry blood away from the heart. They carry oxygen-rich blood. They are usually designated by the color red because oxygen-rich blood is redred.

• Veins generally carry oxygen-poor blood back to the heart from the rest of the body. They are usually designated by the color blue because oxygen-poor blood is a darker color.

Your arteries and veins run to every

location in your body in a

determined path.

Why do you think some people compare our circulatory system to a network of roads?

• Capillaries are microscopic blood vessels that connect arteriesarteries to veins.

• They are where oxygen & waste exchange occur.

• They are only big enough for one blood cell to pass at a time.

Blood Vessels

The Capillaries are in between the artery on the left and the vein on the right

The little donut-shaped red blood cell (scientific name erythrocyte) squeezes through the capillary and drops off its cargo of nutrients and oxygen

Click here for a video of blood flowingin the blood vessels

Circulation• This is the path of the blood through the heart,

lungs, and body.

Follow the arrows in the pictures to trace the flow of blood through the heart, lungs and body.Click here for a silly

circulation song!

Now discuss these review questions:

• What are the functions of the circulatory system?

• What are the major organs of the circulatory system?

• What are the main parts of the heart?• What do arteries and veins do?• How big are capillaries?• What path does blood take as it goes

through your body?• A thinking question: Do you think all living

things have a heart?

Now it’s time for a lab!!

We will be the

volunteers!