Neurons and Synapses
A NEURON is a special kind of cell designed to send and receive signals. Each neuron has three main parts. DENDRITES: branch-like extensions that RECEIVE signals from other neurons. CELL BODY (soma): the central part with the nucleus. AXON: a long thin "wire" that SENDS signals to the next neuron. Some axons are over a meter long (like the ones running down your spinal cord).
SYNAPSES are the tiny gaps where neurons communicate. The signal travels electrically down the axon. At the synapse, the electrical signal triggers the release of NEUROTRANSMITTERS (chemical messengers like dopamine, serotonin, glutamate). They cross the gap and bind to the next neuron's dendrites, triggering a new electrical signal — or sometimes a stop signal. Most learning happens by changing how strongly synapses transmit.
When you LEARN something new, what happens at the cellular level?
Different neurotransmitters do different things. DOPAMINE: reward and motivation. SEROTONIN: mood and well-being. GLUTAMATE: main "go" signal. GABA: main "stop" signal. ACETYLCHOLINE: muscle control and focus. Many medications (antidepressants, ADHD medications, anesthetics) work by adjusting how neurotransmitters work in the brain.
Neuron Sketch
Draw a neuron. Label: dendrites (branchy receivers), cell body, axon (long sender), synapse (the gap to the next neuron). Add a second neuron next to it. Show how the signal would travel.
Every thought you have is electrical signals firing across synapses, in patterns trillions of times more complex than any computer. Knowing how neurons work is the foundation of understanding the mind.
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