Nervous System
The nervous system has three levels of organization:
| Level | Overview |
| Neuron | At the most simple level is the neuron. A neuron is a large, complex cell designed to propagate and transmit chemical and electrical signals to other cells such as muscle fibers or fellow neurons. |
|---|---|
| Local Circuit | Within local circuits, interconnected nerve cells elaborate incoming signals and send the output to other centers or circuits. |
| System | At a higher level, connections among systems (aka pathways) make possible complex behaviors such as reading and speaking. |