This biology lab bridges the gap between individual cell structures and the complex "social network" of the human brain, showing how biological form dictates electrical function.

Activity Description

The Build Your Own Neuron lab is a 3D modeling exercise that allows students to visualize the polarity of a nerve cell—meaning signals only travel in one direction. By using pipe cleaners for the dendrites (inputs) and the axon (output), and beads to represent the insulating myelin sheath, students can literally "see" how the cell is built to carry a signal over a distance. Combining these individual models into a Class Neural Network demonstrates the concept of a synapse (the gap between neurons) and shows how intelligence is not just in the cells themselves, but in the trillion connections between them.

Build Your Own Neuron & Class Neural Network What is a Neuron? Neurons are the nerve cells in your brain and body that send and receive signals. You have about 90 billion neurons in your brain and another 100 billion in the rest of your body, but they are tiny—30,000 could fit on a pinhead! Neurons pass millions of electrical and chemical signals every second, taking messages from your body to your brain and back, helping you sense, move, and function. Some neurons, like those in giraffes, can be very long—up to 5 meters (16 feet)! Neurons connect at points called synapses. The brain has about 100 trillion synapses, forming networks that store memories and information. When you recall an event, these networks send signals to bring together different details—like people, sights, sounds, smells, and emotions. Thinking about something repeatedly strengthens these connections, helping your brain store and retain information. The myelin sheath is a fatty layer that wraps around the axon to speed up the signal. In this lab, the beads on your pipe cleaner represent the myelin sheath, helping your neuron model show how signals travel efficiently along the axon. Neurons are the cells in your nervous system that send and receive signals. Each neuron has four main parts: Part Function Cell body (soma) Control center of the neuron; contains the cell’s “factories” Dendrites Axon Axon terminals Small branches that receive signals from other neurons Long tail that carries signals away from the cell body. Covered in a protective myelin sheath. Branches at the end of the axon that pass signals to other neurons In this activity, you will build a model neuron using pipe cleaners and beads. Afterwards, we will combine all student neurons to make a class neural network. Materials (per student): 2 long pipe cleaners, 4–6 short pipe cleaner pieces,10 white beads, scissors (if needed) Steps to Build Your Neuron 1. Make the cell body: Take one long pipe cleaner and bend it into a circle. This is your cell body. 2. Add dendrites: Twist 2–3 short pipe cleaner pieces onto one side of the cell body and splay them outward. These are your dendrites. 3. Create the axon: Take the second long pipe cleaner and attach one end to the opposite side of the cell body. This is your axon. 4. Thread beads: Slide 10 beads onto the axon pipe cleaner. The beads represent the myelin sheath, a fatty layer that wraps around the axon to speed up the signal. 5. Add axon terminals: Twist 2–3 short pipe cleaner pieces onto the far end of the axon and splay them outward. These are your axon terminals. 6. Trim extras: Cut any extra pipe cleaner ends so nothing sticks out awkwardly. 7. Label your model: On your handout, label the cell body, dendrites, axon, and axon terminals. 8. Class neural network (optional): We will connect all student neurons on the wall to create a large, visual neural network. Reflection Questions 1. Which part of your neuron receives signals? 2. Which part sends signals to other neurons? 3. Why do you think neurons need long axons in your body? 4. How does your neuron model help you understand how messages travel in the brain?