The nervous system functions to receive sensory input, integrate information, and initiate motor responses. It is composed of the central nervous system (brain and spinal cord) and peripheral nervous system (nerves). The two principal cell types are neurons, which transmit electrical signals, and neuroglia or glial cells, which support and insulate neurons. Glial cells include astrocytes, oligodendrocytes, microglia, ependymal cells, Schwann cells, and satellite cells. Neurons have a cell body, dendrites for receiving signals, and an axon for transmitting signals. Axons may be myelinated by glial cells to increase signal speed.

3. Nervous System Figure 11.1

10. Astrocytes Figure 11.3a

12. Microglia and Ependymal Cells Figure 11.3b, c

14. Oligodendrocytes, Schwann Cells, and Satellite Cells Figure 11.3d, e

16. Neurons (Nerve Cells) Figure 11.4b

24. Myelin Sheath and Neurilemma: Formation Figure 11.5a-c

31. Comparison of Structural Classes of Neurons Table 11.1.1

32. Comparison of Structural Classes of Neurons Table 11.1.2

33. Comparison of Structural Classes of Neurons Table 11.1.3