9th grade Neurons and the main parts of the brain worksheet

Neurons and the main parts of the brain

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   A motor-neuron axon can be about 1 m long. Ari reads a card about three axons. An impulse travels the full 1 m length of axon Q. How long does that take?

   • 0.05 s
   • 1 s
   • 0.02 s
   • 20 s
2. 2.

   Each axon is 0.6 m long. Bo compares two axons of the same length. How much sooner does the impulse arrive along axon T than along axon S?

   • 0.28 s sooner
   • 0.3 s sooner
   • 0.02 s sooner
   • 0.32 s sooner

3. Read this first

   Model path card (model data)

   measure	value
   Axon length	0.3 m
   Axon speed	30 m/s
   Chemical synapses on the path	3
   Delay at each chemical synapse	about 1 ms

4. 3.

   Esme adds up the time for a signal on this path. Count only the axon and the chemical synapses, using the delay on the card. What is the total?

   • 30 ms
   • 13 ms
   • 10 ms
   • 3 ms
5. 4.

   Ball-catch path (model, not to scale). Jun sees a ball coming and catches it. Which pair names lobe W and lobe X of the cerebrum?

   • W is the temporal lobe; X is the parietal lobe
   • W is the occipital lobe; X is the frontal lobe
   • W is the occipital lobe; X is the brainstem, which stores the plan
   • W is the occipital lobe; X is the cerebellum, which plans the catch

6. Piano loop (model, not to scale)

   The cerebrum sends a movement plan down the spinal cord to motor neurons, which reach the finger muscles. The cerebrum also sends a copy of the plan to the cerebellum. Sensory neurons from the fingers carry ? to the cerebellum.

7. 5.

   Kira practices the piano. What do the sensory neurons from the fingers carry to the cerebellum?

   • The plan for the next finger movement
   • Orders that make the finger muscles contract
   • Feedback about how the movement is going
   • Memories stored by the cerebellum for the song

8. Notebook on a chemical synapse (model data)

   line	what it says
   1	An electrical impulse runs along the axon to the axon terminals
   2	The axon terminals release neurotransmitter into the gap
   3	The electrical impulse then jumps across the gap into the next neuron
   4	The neurotransmitter binds to receptors on the next neuron

9. 6.

   Milo reviews a classmate's notebook on a chemical synapse. Exactly one line is wrong. Which line, and why?

   • Line 2, because chemicals cannot be released, so the impulse must cross
   • Line 1, because the axon carries chemicals, not impulses
   • Line 4, because the chemicals should bind to the first neuron
   • Line 3, because chemicals, not the impulse, cross the gap

10. Notebook on the brain (model data)

    line	what it says
    1	The cerebrum handles thinking and planned movement
    2	The cerebellum helps with balance and coordination
    3	The brainstem links the brain to the spinal cord and helps keep breathing going
    4	The cerebellum stores long-term memories and makes decisions

11. 7.

    Pia reviews a notebook on three parts of the brain. Exactly one line is wrong. Which line, and why?

    • Line 4, because memory and decisions belong to the cerebrum
    • Line 3, because the brainstem handles memory instead of breathing
    • Line 2, because the cerebellum is for thinking, not balance
    • Line 1, because planned movement belongs to the cerebellum

12. Use this

    Two claims (model data), 2 rows. Columns: claim, what it says. P, One electrical impulse keeps going from the first neuron into the next. Q, An electrical impulse runs along the axon, and chemicals carry the message across the gap.

13. 8.

    Ren compares two claims about a signal crossing a chemical synapse between two neurons. Which choice judges the claims correctly?

    • Claim P is right: one electrical impulse keeps going from neuron to neuron
    • Claim Q is right: the impulse runs along the axon, and chemicals cross the gap
    • Both are right, since signals can move either way, forward or backward
    • Neither is right, since the axon carries chemicals and the gap carries electricity

14. Use this

    Two claims (model data), 2 rows. Columns: claim, what it says. P, Sensory neurons carry messages from the skin to the spinal cord, and motor neurons carry messages from the spinal cord to muscles. Q, Motor neurons bring news in from the skin, and sensory neurons tell muscles what to do.

15. 9.

    Tala compares two claims about neuron types. Which choice judges the claims correctly?

    • Neither is right, since interneurons do the work of a reflex alone
    • Claim Q is right: motor neurons bring the news in, and sensory neurons order the move
    • Claim P is right: sensory neurons carry messages in, and motor neurons carry them out
    • Both are right, since neurons carry messages in either direction

16. Use this

    Two claims (model data), 2 rows. Columns: claim, what it says. P, The cerebellum does the thinking, and the brainstem stores memories. Q, The cerebrum does the thinking and holds memory, the cerebellum helps with balance, and the brainstem helps keep breathing going.

17. 10.

    Zee compares two claims about the main parts of the brain. Which choice judges the claims correctly?

    • Both are partly right: the brainstem stores memories, and the cerebellum helps breathing
    • Claim P is right: the little brain thinks, and the brainstem stores memories
    • Claim Q is right: the cerebrum thinks, the cerebellum balances, the brainstem helps breathing
    • Neither is right, since the three parts share the same jobs