| A | B |
|---|
| neuron | basic building block of nervous system |
| dendrite | branching extension of neuron to receive messages and conduct impulses toward cell body |
| axon | extension of neuron through which messages pass to other neurons, muscles, or glands |
| myelin sheath | layer of fatty tissue segmentally covering axon; enhances transmission of neural impulses |
| synapse | junction between axon of sending neuron and dendrite or body of recieving neuron |
| neurotransmitter | chemical messengers that cross synaptic gaps |
| nervous system | body's electrochemical communication system |
| central nervous system (CNS) | brain and spinal cord |
| reflex | simple, automatic, inborn response to sensory stimulation |
