Bones, muscles and the senses

Grade 7 Science Worksheet

Circle the best answer.

1. 1.

   Ari learns that a person's eye is healthy, but the optic nerve is damaged. What will most likely happen?

   • The brain sees the light directly through the eye, so sight is the same as before.
   • The retina can no longer detect light, so the optic nerve has nothing to send to the brain.
   • The lens cannot focus any more, so images are blurry but the person can still see.
   • The retina still detects light, but the signal cannot reach the brain, so sight is lost.
2. 2.

   The three small bones in Bo's middle ear are stiff. Sound still reaches the eardrum. What will most likely follow?

   • The eardrum cannot vibrate, so no sound enters the ear and nothing is heard.
   • The auditory nerve stops carrying signals, so sounds seem the same but are not stored.
   • Vibrations pass poorly from the eardrum to the cochlea, so sounds seem quieter.
   • The cochlea makes sounds louder, so the stiff bones make hearing sharper than before.
3. 3.

   A drum sounds near Esme. Which list puts the path of the sound signal in order?

   • Cochlea → three small bones → eardrum → auditory nerve → brain
   • Eardrum → auditory nerve → three small bones → cochlea → brain
   • Brain → auditory nerve → cochlea → three small bones → eardrum
   • Eardrum → three small bones → cochlea → auditory nerve → brain
4. 4.

   Jun touches a hot pan and pulls the hand back before feeling the pain. Which path best fits the reflex?

   • Skin receptor → sensory neuron → spinal cord → motor neuron → arm muscle
   • Skin receptor → sensory neuron → spinal cord → brain, with no signal to the arm muscle
   • Skin receptor → sensory neuron → brain → motor neuron → arm muscle, then spinal cord
   • Arm muscle → motor neuron → spinal cord → sensory neuron → skin receptor
5. 5.

   Distance the ruler fell before the catch, in cm. Ari: 12, 14, 13. Bo: 22, 20, 24. Kira runs a ruler-drop test. A shorter catch distance means a quicker response. Whose reaction is quicker?

   • Ari's, because the ruler fell a shorter distance before Ari caught it each time.
   • They are equal, because each person was tested three times with the same ruler.
   • Bo's, because the ruler fell a longer distance, which shows Bo had more time to react.
   • Ari's, because 12 is the smallest number and the first number in the table.
6. 6.

   Catch distance in cm. Try 1: 24. Try 2: 21. Try 3: 19. Try 4: 17. Try 5: 17. Luz practices the ruler-drop test five times. A shorter catch distance means a quicker response. What does the table best show?

   • The response got slower with practice, since the distances became smaller each try.
   • The response got quicker on each try, since the last two tries are equal.
   • The response stayed the same, since the same person caught the ruler on each try.
   • The response got quicker with practice at first, then leveled off at 17 cm.
7. 7.

   Average catch distance for 8 students. Signal seen: 16 cm. Signal felt as a tap: 13 cm. Noah catches a ruler by sight, then catches it with eyes closed when a partner taps a shoulder as the signal. What do the averages suggest?

   • Responding to a sight is quicker, since 16 cm is a bigger number than 13 cm.
   • Responding to a tap seems a little quicker than to a sight, but 8 students is a small test.
   • Touch is quicker than sight for any person, since the tap gave a shorter distance.
   • The two signals give the same speed, since the difference is just 3 cm.

8. Read this first

   Table (model data)

   Joint P: bends and straightens in one direction. Joint Q: swings forward, back, out to the side and around in a circle. Joint R: turns a bone from side to side around another bone.

9. 8.

   Pia records how three joints can move. Which match of joint to type is correct?

   • P is a hinge, Q is a pivot, and R is a ball-and-socket.
   • P is a ball-and-socket, Q is a hinge, and R is a pivot.
   • P is a pivot, Q is a ball-and-socket, and R is a hinge.
   • P is a hinge, Q is a ball-and-socket, and R is a pivot.
10. 9.

    Ren bends the knee to pull the foot back, as when kicking backward. Which muscle group contracts?

    • The calf muscles stretch so that the lower leg is pushed back behind the knee.
    • The quadriceps on the front of the thigh contract and pull the lower leg back.
    • The hamstrings on the back of the thigh contract and pull the lower leg back.
    • The quadriceps on the front of the thigh relax and push the lower leg back.
11. 10.

    Zee hears that the Achilles tendon joins the calf muscle to the heel bone. What does this tell about how the foot moves?

    • When the calf muscle shortens, the tendon pulls the heel bone, which lifts the heel.
    • The tendon holds the heel bone to the leg bones, so the calf muscle is not needed to lift the heel.
    • When the calf muscle shortens, the tendon pushes the heel bone, which lifts the heel.
    • The tendon makes the heel bone move by itself, so the calf muscle just holds the heel up.