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The Nervous System: Two Parts, One Fast Team

Science · The Human Body · ages 9-11

Name ______________________ Date ____________

Which two body parts make up the central nervous system?
- Heart and stomach working together
- Brain and spinal cord
- Skin and muscles
What are the two main parts of the nervous system?
- Central and peripheral nervous system
- Muscles and bones all over your body and face
- Heart and lungs
Nerves only exist in your brain, not anywhere else in your body.
Circle one: True False
Jay steps on a sharp rock. What is the correct order of his reflex?
- Stimulus, sensory nerve, spinal cord, motor nerve, muscle moves
- Muscle moves, motor nerve, spinal cord, sensory nerve, stimulus
- Sensory nerve, muscle moves, stimulus
In this reflex arc, what happens at the step marked with a question mark?
- The stomach digests food
- The eyes blink on their own to keep them wet and safe
- The spinal cord reacts and sends a signal back
Why can you pull your hand off a hot stove before you even feel the full pain?
- Because your hand moves before your body sends any message at all
- Because nerve signals travel very fast to and from your spine
- Because pain travels slower than sound
A doctor taps just below a patient's knee, and the leg kicks out on its own. Which part of the nervous system made that fast, automatic response possible?
- The peripheral nerves and spinal cord working as a reflex arc
- Only the muscles, with no nerves involved
- Only the brain, thinking very carefully about the tap first, not quickly
Zara says: 'My brain has to think about it every time before I blink when something flies at my eye.' What is wrong with what she said?
- Nothing is wrong, brains always think before every single movement
- Blinking only happens if the peripheral nervous system is missing from the body
- Blinking at something flying at your eye is a fast reflex, not a decision

Answer key

For grown-ups. Fold this page away before handing over the rest.

The Nervous System: Two Parts, One Fast Team W1-mt_qzbgwaUQOA-s1

Brain and spinal cord · Together, the brain and spinal cord form your central nervous system, the body's command center.
Central and peripheral nervous system · The central nervous system is the brain and spinal cord. The peripheral nervous system is the nerves that reach the rest of your body.
False · Nerves branch out from your spinal cord to reach your entire body. That network is called the peripheral nervous system.
Stimulus, sensory nerve, spinal cord, motor nerve, muscle moves · A reflex always starts with a stimulus and ends with the muscle responding, with the sensory nerve, spinal cord, and motor nerve in between.
The spinal cord reacts and sends a signal back · The spinal cord (sometimes with the brain) receives the sensory signal and sends out the motor command instantly.
Because nerve signals travel very fast to and from your spine · Nerve signals move at high speed, so your body can react in a reflex before the pain feeling fully forms in your brain.
The peripheral nerves and spinal cord working as a reflex arc · The knee-jerk reflex is a classic example of a reflex arc: sensory nerves send the signal to the spinal cord, which immediately sends a motor signal back to the muscle.
Blinking at something flying at your eye is a fast reflex, not a decision · Reflexes like blinking use the fast sensory nerve to spinal cord to motor nerve pathway, so your body reacts before your brain fully processes the danger.