Guide 04 / six systems
Nervous system
The body’s fast communication network, turning sensation into meaning and intention into action.
The job
Detects change, processes information, coordinates movement, and regulates rapid responses.
Orient yourself
Start with the central nervous system, brain and spinal cord, then follow the peripheral nerves outward. Sensory pathways carry information in; motor pathways carry instructions out. Both are coordinated rather than isolated.
Trace a pathway
A reflex is a clean first example: a receptor detects a stimulus, a sensory neuron carries the signal into the spinal cord, an interneuron coordinates the response, and a motor neuron activates a muscle.
Make the connection
- The spinal cord is both a protected communication cable and a local processing center.
- Specialized sensory receptors translate light, pressure, sound, and chemicals into neural signals.
- The autonomic nervous system adjusts organs without requiring conscious attention.
Close the page
Can you explain it without looking?
Active recall turns recognition into understanding. Answer these prompts in your own words, then return to the guide only for the part you could not reconstruct.
What is the difference between central and peripheral nervous systems?
Why can a reflex happen before conscious awareness?
Which direction does a sensory neuron carry information?