The Nervous System
Understand that the nervous system has two parts — the central nervous system (brain and spinal cord) and nerves that branch throughout the body — and that nerve signals travel at high speed to coordinate senses, thought, and movement
What a learner can do afterwards
- Name the two parts of the nervous system: central (brain + spinal cord) and peripheral (nerves throughout the body)
- Describe the reflex arc: stimulus → sensory nerve → spinal cord/brain → motor nerve → muscle response
- State that nerve signals travel extremely fast, which is why reflexes happen almost instantly
The lesson
Your nervous system is your body's message system. It has two parts that work together every second of the day: the central nervous system and the peripheral nervous system.
The central nervous system is your brain and spinal cord. It is command central, where signals get read and decisions get made. The peripheral nervous system is every other nerve in your body. These nerves branch out from your spinal cord like the branches of a tree, reaching your fingers, toes, skin, and everywhere else.
Mia touches a hot pan by accident. Sensory nerves in her skin fire a signal that races to her spinal cord. Her spinal cord fires back a motor signal right away, and her hand yanks back, all before the pain even fully registers in her mind.
Nerve signals travel incredibly fast, some almost as fast as a race car. That speed is exactly why reflexes feel instant.
Two parts, one team: your brain and spinal cord decide, and nerves reaching through your whole body carry the message at incredible speed.
Watch it
Where it sits
This opens up
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.