Neurons and the main parts of the brain
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
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?
- 20 s
- 1 s
- 0.02 s
- 0.05 s
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?
- 0.3 s sooner
- 0.02 s sooner
- 0.28 s sooner
- 0.32 s sooner
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 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
- 10 ms
- 13 ms
- 3 ms
A gust of wind tips Luz's bike a little. Which sequence shows how the body corrects the tilt?
- Sensory neurons report the tilt, the brainstem stores it as a memory, motor neurons carry the memory
- Sensory neurons report the tilt, the cerebellum compares it with the plan, motor neurons carry the fix
- Motor neurons report the tilt, the cerebellum compares it with the plan, sensory neurons carry the fix
- Sensory neurons report the tilt, the cerebellum decides where to ride next, motor neurons carry the choice
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 Milo reviews a classmate's notebook on a chemical synapse. Exactly one line is wrong. Which line, and why?
- Line 1, because the axon carries chemicals, not impulses
- Line 4, because the chemicals should bind to the first neuron
- Line 2, because chemicals cannot be released, so the impulse must cross
- Line 3, because chemicals, not the impulse, cross the gap
Notebook on a reflex (model data)
line what it says 1 A receptor in the skin starts the signal 2 A sensory neuron carries the message out to the muscle 3 An interneuron in the spinal cord links the sensory neuron to the motor neuron 4 A motor neuron carries the message to the muscle Noah reviews a notebook on a reflex. Exactly one line is wrong. Which line, and why?
- Line 2, because sensory neurons carry messages in, not out to muscles
- Line 3, because interneurons belong in the brain, not the spinal cord
- Line 4, because motor neurons carry messages in from the muscle
- Line 1, because the receptor is part of the muscle
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 Pia reviews a notebook on three parts of the brain. Exactly one line is wrong. Which line, and why?
- Line 3, because the brainstem handles memory instead of breathing
- Line 2, because the cerebellum is for thinking, not balance
- Line 4, because memory and decisions belong to the cerebrum
- Line 1, because planned movement belongs to the cerebellum
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.
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
- Neither is right, since the axon carries chemicals and the gap carries electricity
- Both are right, since signals can move either way, forward or backward
- Claim Q is right: the impulse runs along the axon, and chemicals cross the gap
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.
Tala compares two claims about neuron types. Which choice judges the claims correctly?
- 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
- Claim Q is right: motor neurons bring the news in, and sensory neurons order the move
- Neither is right, since interneurons do the work of a reflex alone
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.
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
- Neither is right, since the three parts share the same jobs
- Claim Q is right: the cerebrum thinks, the cerebellum balances, the brainstem helps breathing