Chapter

10

Key Terms

Acetylcholine................ 235 Endorphins.................. 241 Nucleus..................... 242
Acetylcholinesterase.......... 241 Ependymal cells.............. 235 Oligodendroglia............. 235
Action potential.............. 239 Ganglia..................... 242 Parasympathetic division...... 235
Adrenaline/epinephrine....... 241 Glial cells................... 235 Peripheral nervous system

Afferent peripheral system.... 234 Gray matter................. 242

(PNS).......

.............. 234
All-or-none law.............. 241 Horns...................... 242 Pia mater................. 242
Anterior or ventral gray horn.. 243 Internuncial or association Posterior or dorsal gray horn... 243

Anterior or ventral root....... 243

neurons..

................. 239 Posterior or dorsal root........ 243
Arachnoid mater............. 242 Membrane or resting Reflex...................... 241

Astrocytes.................. 235

potential.

................. 239 Reflex arc................... 241
Autonomic nervous Meninges................... 242 Repolarization............... 239
system (ANS)...........
... 234 Microglial cells............... 235 Schwann cells/

Axon....................... 236 Motor or efferent neuron...... 239

neurolemmocytes.......

... 235
Axon terminals.............. 236 Multipolar neurons........... 237 Sensory or afferent neuron.... 239
Bipolar neurons.............. 238 Myelin sheath............... 235 Serotonin................... 241
Central nervous system Nerve.................... 235 Somatic nervous system....... 234
(CNS)..................
... 233 Neuroglia................... 235 Spinal meninges............. 242
Cortex...................... 242 Neurons.................... 235 Sympathetic division.......... 234
Dendrites................... 236 Nissl bodies/chromatophilic Synapses................... 241

Depolarization............... 239
substance................. 236 Tract....................... 242
Dopamine................... 241 Nodes of Ranvier/neurofibril Unipolar neurons............. 238

Dura mater.................. 242

nodes...

................. 237

White matter....

............ 242
Efferent peripheral system..... 234 Norepinephrine.............. 234

Introduction

The nervous system is the body’s control center and
communication network. It directs the functions of the
body’s organs and systems. It allows us to interpret what is
occurring- in our external environment and helps us to
decide how to react to any environmental change or stim-
ulus by causing muscular contractions. It shares in the
maintenance of homeostasis (the internal environment of
our bodies) with the endocrine system by control-ling the
master endocrine gland (the pituitary) through

the hypothalamus of the brain. See Concept Map 10-1:

Spinal- Cord and Spinal Nerves.

Organization

The nervous system can be grouped into two major

categories (Figure 10-1). The first is the central nervous

system (CNS), which is the control center for the whole

system. It consists of the brain and spinal cord. All body

sensations and changes in our external environment