Your Nervous System: Signals and Responses

Year 10 Science Understanding how your body coordinates responses to stimuli Exploring neurons, impulses, and synapses

Think About This...

How does your hand know to pull away from a hot stove before you even think about it? What happens in your body in that split second? How fast do you think this response occurs?

The Central Nervous System

Brain: Control center processing information Spinal cord: Highway for nerve signals Together they coordinate all body responses Protected by bone (skull and vertebrae) Contains billions of specialized cells called neurons

Structure of a Neuron

How Nerve Impulses Travel

{"left":"Stimulus detected by sensory receptors\nElectrical signal travels along dendrites to cell body\nSignal processed and passed to axon\nElectrical impulse speeds down axon (up to 120 m/s!)","right":"Signal reaches axon terminal\nChemical neurotransmitters released into synapse\nNext neuron receives chemical signal\nProcess repeats until signal reaches brain or target organ"}

Model the Reflex Arc

Work in pairs to trace a reflex response Choose a stimulus: hot object, loud noise, or bright light Map the pathway: Receptor → Sensory neuron → Spinal cord → Motor neuron → Muscle Time how fast you can demonstrate the reflex Advanced: Research a neurological condition that affects reflexes

Synapses: The Neural Gaps

Tiny gaps between neurons (0.02 micrometers) Electrical signals cannot jump across Chemical neurotransmitters bridge the gap Over 100 different types of neurotransmitters Disruption here causes many neurological disorders

Key Takeaway

"The nervous system is your body's electrical wiring and chemical messaging system, coordinating split-second responses that keep you safe and help you interact with the world."