The circulatory and respiratory systems working together

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. Read this first

   Lung oxygen card (textbook facts)

   place	oxygen (mm Hg)
   air in the alveoli	100
   blood arriving in the lung capillaries	40
   blood leaving the lungs in the pulmonary veins	100

2. 1.

   Pia reads a card of oxygen at the lungs. Using the card and the route of blood, which statement is true?

   • Oxygen diffuses into the blood at the alveoli, and the pulmonary veins carry it to the left atrium
   • Oxygen diffuses into the blood at the alveoli, and the pulmonary veins carry it to the right atrium
   • The lungs make oxygen that enters the blood, and the pulmonary veins carry it to the left atrium
   • Oxygen diffuses into the blood at the alveoli, and the pulmonary arteries carry it to the left atrium

3. Run card (model data)

   state	heart rate (beats per minute)	breathing rate (breaths per minute)
   resting	75	14
   running	150	40

4. 2.

   Ren reads the run card. Which statement uses both the breathing column and the heart column to explain how muscles get more oxygen?

   • Faster breathing means the lungs make more oxygen for a faster heartbeat to carry
   • Faster breathing takes in more oxygen, and a faster heartbeat carries it to the muscles sooner
   • A faster heartbeat sends blood from the left side to the lungs more often
   • A faster heartbeat brings in more oxygen, and faster breathing carries it to the muscles

5. Rest model card (model data)

   case	stroke volume (mL per beat)	cardiac output (mL per minute)	heart rate (beats per minute)
   now	70	5,250	75
   changed	105	5,250	?

6. 3.

   Tala edits a model of rest. Cardiac output stays at 5,250 mL per minute while stroke volume rises from 70 mL to 105 mL. What happens to heart rate?

   • It rises to 112 beats per minute, because a bigger beat needs a faster rhythm
   • It stays at 75 beats per minute, because cardiac output did not change
   • It rises to 100 beats per minute, because the heart must keep up the output
   • It falls to 50 beats per minute, because each beat moves more blood

7. Lung gradient card (model data)

   time	oxygen in alveolar air (mm Hg)	oxygen in blood arriving (mm Hg)
   at rest	100	40
   during a run	100	30

8. 4.

   Zee edits a model of a run. Blood arriving at the lungs holds less oxygen than at rest. What follows at the alveoli?

   • Oxygen stops moving, because the blood no longer needs any more
   • Oxygen moves into the blood faster, because the difference in oxygen is larger
   • The lungs make extra oxygen to fill the gap in the blood
   • Oxygen moves into the blood more slowly, because the blood has less to give

9. Run model card (model data)

   model run	vessels to the leg muscles	blood to the leg muscles (mL per minute)
   run A	widen	9,000
   run B	narrow	?

10. 5.

    Ari edits a model of a run. In run B, vessels to the leg muscles narrow instead of widening. What does the model predict for run B?

    • More than 9,000 mL per minute, so the muscles get more oxygen
    • Less than 9,000 mL per minute, so the muscles get less oxygen
    • More than 9,000 mL per minute, since blood is squeezed through a narrow vessel
    • The same 9,000 mL per minute, since the width of a vessel does not matter
11. 6.

    Esme reviews a classmate's notebook on blood vessels. Exactly one line is wrong. Which line, and why?

    • Line 3, because the swap of gases happens in the large arteries and veins
    • Line 1, because arteries carry blood toward the heart and veins carry it away
    • Line 2, because veins carry blood away from the heart and arteries carry it back
    • Line 4, because the pulmonary arteries carry oxygen-poor blood
12. 7.

    Jun reviews a classmate's notebook on gas exchange. Exactly one line is wrong. Which line, and why?

    • Line 4, because carbon dioxide diffuses from the air into the blood at the alveoli
    • Line 3, because the lungs take oxygen from the air and do not make it
    • Line 1, because the blood arriving in the lungs holds more oxygen than the air
    • Line 2, because diffusion moves oxygen from low amounts to high amounts

13. Exercise card (model data)

    state	heart rate (beats per minute)	stroke volume (mL per beat)	cardiac output (mL per minute)
    resting	75	70	5,250
    running	150	100	15,000

14. 8.

    Kira reads the exercise card. Which statement does the card support?

    • Cardiac output doubled, just like heart rate, because stroke volume did not matter
    • Cardiac output grew by less than double, because stroke volume fell
    • Cardiac output grew to more than double, because stroke volume rose as well as heart rate
    • Cardiac output stayed about the same, because the rises in rate and volume cancel
15. 9.

    Luz reads a graph of heart rate during and after a run. Which statement does the graph support?

    • After the run stopped, heart rate was back to 75 by minute 10
    • After the run stopped, heart rate kept rising until minute 10
    • After the run stopped, heart rate fell but was still above 75 at minute 10
    • Heart rate was highest at minute 10, after the run stopped

16. Blood flow card (model data)

    place	at rest (mL per minute)	during a run (mL per minute)
    leg muscles	1,200	9,000
    digestive organs	1,400	300

17. 10.

    Milo reads the blood flow card for a rest and a run. Which statement does the card support?

    • During the run, the digestive organs got 1,100 mL less per minute, so their vessels widened
    • During the run, the leg muscles got 7,800 mL more per minute, so their vessels narrowed
    • During the run, the leg muscles got 7,800 mL more per minute, so their vessels widened
    • During the run, the leg muscles got 9,000 mL more per minute, so their vessels widened