The nervous system is the body’s fast communication network. It helps you sense light, sound, touch, temperature, pain, smell, and taste. It also helps control movement, balance, breathing, heartbeat, digestion, memory, and emotions.
Understanding how it works helps students connect health, behavior, and body function.
Key Facts
- The central nervous system includes the brain and spinal cord.
- The peripheral nervous system includes nerves that branch through the body.
- Neurons send messages using electrical impulses and chemical signals.
- Signal speed can be over 100 m/s in some myelinated neurons.
- A reflex can travel through the spinal cord before the brain fully processes it.
- Healthy habits such as sleep, exercise, hydration, nutrition, and helmets help protect nervous system function.
Vocabulary
- Brain
- The brain is the control center that processes information, makes decisions, stores memories, and coordinates body activities.
- Spinal cord
- The spinal cord is a thick bundle of nerve tissue that carries messages between the brain and the rest of the body.
- Neuron
- A neuron is a specialized nerve cell that sends and receives signals.
- Nerve
- A nerve is a bundle of neuron fibers that carries signals to and from body parts.
- Synapse
- A synapse is the tiny gap where one neuron passes a message to another cell using chemical messengers.
Common Mistakes to Avoid
- Thinking the brain works alone is wrong because the spinal cord and peripheral nerves are essential pathways for signals throughout the body.
- Confusing nerves with blood vessels is wrong because nerves carry information signals while blood vessels carry blood, oxygen, and nutrients.
- Assuming all body actions require conscious thought is wrong because many actions, such as reflexes, breathing changes, and balance adjustments, can happen automatically.
- Forgetting that nerve signals move in organized pathways is wrong because sensory signals usually travel toward the central nervous system and motor signals usually travel away from it.
Practice Questions
- 1 A nerve signal travels at 50 m/s. How long does it take to travel 1.5 m from a foot to the spinal cord?
- 2 A student reacts to a sound in 0.25 s. If the signal pathway is about 2.0 m long in total, what is the average signal speed along that pathway?
- 3 Explain why pulling your hand away from a hot surface can begin before you are fully aware of the pain.