Primary 3 · Science · Systems: Respiratory & Circulatory
Systems: Respiratory & Circulatory questions for Primary 3 Science
9 questions to work through online, 2 of them written out the way the paper asks. Answer and you get the working straight away, then a score at the end. No sign-up, and you can retake it as often as you like.
- Path of air
- Breathing out
- What the lungs do
- What the heart does
- What exercise changes
- What blood carries
- Reasoning about the systems
- Naming a part
- Naming the gas
Same picture as the question above.
| When measured | Heartbeats per minute | Breaths per minute |
|---|---|---|
| sitting still | 80 | 16 |
| after skipping | 132 | 31 |
Answers and explanations for all 9 questions
Every answer with the reasoning behind it. Worth reading after you have tried the set — or on its own, if you are a parent marking it.
According to the diagram above, where does air go after it passes through the windpipe?
Answer: R
After the windpipe, air reaches R, which is the lungs.
Using the same diagram, which path does air take when you breathe out?
Answer: R, then Q, then P
Breathing out is the same path in reverse: R, then Q, then P — lungs, windpipe, nose.
What is the main job of the lungs?
Answer: to take oxygen from the air into the blood
The lungs are where the air meets the blood: oxygen from the air passes into the blood, and waste gas passes out.
What is the main job of the heart?
Answer: to pump blood to every part of the body
The heart is a pump. It pushes blood out so that every part of the body gets the oxygen and food the blood carries.
Based on the table above, which statements are correct?
Answer: A, B and C only
Both numbers went up: 80 to 132 heartbeats and 16 to 31 breaths. Exercising muscles need more oxygen, so the body breathes faster to take it in and pumps faster to deliver it.
What does blood carry around the body?
Answer: A, B and C
Blood carries all three: oxygen from the lungs, digested food from the small intestine, and waste away from the cells that made it.
Why does a person breathe faster when they run?
Answer: Their muscles need more oxygen than usual.
Running muscles use oxygen faster than resting ones. Breathing faster takes in more oxygen to keep up with them.
Look at the part labelled Q in the diagram above. What is the name of this part?
Answer: windpipe
Q is the windpipe, the tube between the nose and the lungs.
The lungs take one gas out of the air we breathe in and pass it into the blood. Which gas is that?
Answer: oxygen
The gas taken from the air into the blood is oxygen.