Neurons

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

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)

Central Nervous System 1 Sensory receptor 2 Sensory neuron Brain 3 Motor neuron Spinal cord Quadriceps muscles 4 Interneuron Central Nervous System Nerve Flexor muscles Figure 28.1B