So what is a neuron, exactly? A neuron is a type of cell. Your body is made up of cells, 10 trillion of them! That over 100 brains’ worth of cells. Neurons are a type of special type of cell that send, receive, and store electrical and chemical information. A neuron has three parts:
|A neuron. The neurons in the visual, motor, memory and language centers of my brain, as well as in my eyes and muscles, all had to talk to each other so that I could draw this picture.|
The soma is the neuron’s control center. It keeps the neuron healthy, produces all the proteins and chemicals that a neuron needs to function, and holds the neuron’s DNA.
The axon sends information to other neurons. It can be extremely long. You have an axon that goes from your spinal cord all the way to the tip of your big toe. The axon conducts information much like an electrical wire. (More on this in a future post.)
The dendrite receives information from other neurons. It joins up with another neuron’s axon at a junction called a synapse, which is a whole big future blog post in itself. Dendrites are shorter than axons, and highly branched. They look a lot like trees, which is why we often call them “dendritic arbors.” (“Arbor” means “tree”.)
When one neuron has an important message to send (like, “Ow-wow! Get your hand off that hot plate!”), it sends the message as an electrical signal down its axon. This message is called an action potential. The dendrite of the next neuron in line (I’ll call it neuron #2) picks up the signal and sends it to its soma. If the signal is strong enough, it triggers a new action potential in neuron #2’s axon, which signals to the dendrite of neuron #3, and so on until you pull your hand off the hot plate.
That’s Neurons 101. Coming up are how the action potential works, what’s a synapse, and more about how your muscles respond to that hot plate.