CHAPTER 48: NERVOUS SYSTEM I. Endocrine vs. Nervous Nervous Complexity Structure Communication Response Time II. Nervous systems perform 3 overlapping functions 1. 2. 3. functions involve both parts: 1. Central nervous system (CNS): 2. Peripheral nervous system (PNS): III. Nervous system composed of neurons & supporting cells A. Neurons: cell body: dendrites: axons: synapse; neurotransmitters: 3 types of neurons: 1. 2. 3. Endocrine IV. B. Supporting Cells: glial cells: astrocytes: oligodendrocytes: Schwann cells: Why insulate? Impulses are action potentials A. Origin of Electrical Membrane Potential * * * B. Membrane Potential Changes & The Action Potential * * * * * * * C. Propagation of Action Potential * * * D. Action Potential Transmission Speed factors affecting speed of potential propagation: 1. 2.