Nerve Cells “Talk” to Each Other
The Nervous System Has Sensory, Motor,
and Integrative Functions
Neurons Are Electrically Excitable Cells
Designed for Transmitting Information
Neuroglia Protect Neurons and Help Them
Do Their Jobs
Action Potentials Help Propagate Nerve
Impulses Along the Nerve Fiber
Synapses Help Neurons Communicate
with Other Cells
The Central Nervous System Coordinates
All Nervous Activity
The Central Nervous System Requires Protection
The Brain Is Composed of Many Different Parts
■ WHAT A HEALTH PROVIDER SEES:
Alzheimer Disease
The Spinal Cord Helps the Brain
Communicate with the Environment
The Autonomic Nervous System Controls
the Activities of Smooth Muscle, Cardiac
Muscle, and Glands
The ANS Uses a Two-Neuron Pathway to
Communicate with the Effectors
The Sympathetic D ivision of the ANS:
Fight-or-Flight Responses
The Parasympathetic Division of the ANS:
A Rest-and-Digest Response
The Peripheral Nervous System
Communicates with the Outside World
Cranial Nerves Originate from Brain Tissue
Spinal Nerves Contain Both Sensory and Motor
Fibers That Supply a Specific Area of the Body
Reflex Arcs Allow Automatic Responses
to a Stimulus
The Nervous System
Somatic Senses and Special Senses
Somatic Senses Are Related to Detection of
Pressure, Chemicals, Proprioception, and Touch
228
Receptors Help Monitor the Internal and
External Environments
229
■ WHAT A HEALTH PROVIDER SEES:
Pain Management
231
Sensations Are Evaluated in Various Places
in the CNS
232
Some Special Senses Use Receptors
That Detect Chemicals
232
Receptors for Olfaction Lie Within the Nasal Cavity
232
Gustation Involves Receptors from Both
the Oral and Nasal Cavities
233
Vision Involves Photoreceptors in the Eyes
235
Accessory Structures Protect the Eyeball and
Muscles Allow It to Move
235
The Eyeball Is Composed of Three Structural Layers 236
Light Is Focused Using Refraction and
Accommodation
238
Signals Travel from the Eye to the Brain
240
The Ear Is Involved in Hearing and Equilibrium
241
The Ear Is Composed of Three Distinct Regions
241
Receptors for Hearing Are Found in the Cochlea
243
Equilibrium Comes in Two Varieties:
Static and Dynamic
244
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Contents xxv
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