1. Neurons

2. Signal direction
Dendrites
Cell body
Cell body
Myelin sheath
Signal pathway
Axon
Nucleus
Myelin sheath

3. Three types of neurons correspond to the nervous system’s three main functions:
Sensory neurons convey signals from sensory receptors in the skin to the central nervous system
Interneurons integrate data and relay signals
Motor neurons convey signals to effectors (muscles)

4. Central Nervous System1
Sensory receptor 2
Sensory neuron
Brain 3
Motor neuron
Spinal cord
Quadriceps muscles 4
Interneuron
Central Nervous System
Nerve
Flexor muscles
Figure 28.1B