1. The Pumping Heart

2. Learning Goal
Use a model to explore the double-pump action of the heart.
Determine the direction of the flow of blood through the heart.
Recognize that humans have a closed circulatory system.
Understand the purpose of valves in the heart.

3. Your heart valves at work
Review
The Arteries carry blood Away from the heart.
The VeINs carry blood INto the heart.
Our blood supply is constant – you have about 2-3 liters; an adult has 5-6 liters.
The same blood circulates throughout your body.
Your heart valves at work

4. Materials
2 plastic cups
2 heart pumps
1 plastic box
Water
Lab sheet

5. Read your entire lab sheet.
Try to picture what you will set up.
Notice, you need to draw a picture of your set-up on the back before you clean up and put it away.
Also note that you need to show your system to Mrs. Ryan and explain it to her before you can add water.
Fill cups only halfway with water.

6. The Pump Action
The heart (plastic pumps) pump blood to CUP 1 – THE LUNGS.
The lungs add oxygen.
The pump sends the oxygen-rich blood to CUP 2 – THE BODY.
The body uses the oxygen then returns it to the heart.
The heart pumps it to CUP 1 – THE LUNGS again and the cycle repeats.

9. Possible Answers
What causes the sounds that you hear when operating the heart? The vibrations resulting from the closing of the valves. As the ventricles contract, the valves between the atria and ventricles close (the “lub”); when the atria contract, the valves between the ventricles and arteries close (“dub”)
B. Why is the heart considered a double-pump? The right side pumps blood to the lungs; the left side pumps blood to the rest of the body
C. What is the function of the valves The valves prevent the backflow of blood into the heart. (heart murmur)
D. What do we mean when we say humans have a “closed” circulatory system? Human blood is confined within vessels.

10. Blood Pressure

11. Blood Pressure
The force exerted by the blood on the walls of the arteries.
Brainpop: Blood Pressure click Tim
Think of water being pumped through a hose – the narrower the hose, the greater the pressure inside of it; the farther the water travels from the pump – the lower the pressure becomes..

12. Blood Pressure Disorders
Hypotension – low blood pressure
Sometimes from old age
Hypertension – high blood pressure
Race, diet, age, heredity, stress, obesity, salt, inactive lifestyle, some medications, smoking
Atherosclerosis - hardening or narrowing of the artery walls; plaque forms
Brainpop: fats
Aneurysm - bulging weak spot on artery walls
Stroke – ruptured blood vessel or clot that blocks the passage