The Heart's Double Loop

Science · The Human Body · ages 9-11

Name ______________________ Date ____________

Which blood vessels carry blood away from the heart?
- Veins
- Arteries
- Capillaries
How many chambers does the heart have?
- 4
- 2
- 6
Plasma is the liquid part of blood.
Circle one: True False
Which blood cells fight off germs and infection?
- White blood cells
- Red blood cells
- Platelets
Blood leaves the heart, picks up oxygen in the lungs, then returns to the heart. Where does it go next?
- Back to the lungs
- Straight to the kidneys only
- Out to the rest of the body
Where does the exchange of oxygen and waste happen between blood and body tissues?
- In the arteries
- In the capillaries
- In the veins
A cut on your finger stops bleeding after a few minutes. Which part of the blood makes this happen?
- Platelets
- Red blood cells
- Plasma
Ravi says veins carry blood away from the heart and arteries carry it back. What's wrong with this?
- He is correct
- Capillaries do that job, not veins or arteries
- He has it backwards: arteries carry blood away, veins carry it back

Answer key

For grown-ups. Fold this page away before handing over the rest.

Arteries · Arteries carry blood away from the heart. Veins bring it back.
4 · The heart has four chambers: two atria on top and two ventricles below them.
True · Plasma is the watery liquid that carries the blood cells and platelets around.
White blood cells · White blood cells are the body's defenders against infection.
Out to the rest of the body · After the lung loop, the heart pumps the oxygen-rich blood out on its second loop, to the rest of the body.
In the capillaries · Capillaries have walls so thin that oxygen and waste can pass right through them.
Platelets · Platelets clump together at a cut to help the blood clot and seal it up.
He has it backwards: arteries carry blood away, veins carry it back · Arteries carry blood away from the heart, and veins carry it back. Ravi swapped the two.