7
CHAPTER SUMMARY
The nervous system is the body’s fast-acting master controller. It monitors changes inside and outside
the body, integrates sensory input, and effects an appropriate feedback response. In conjunction with
the slower-acting endocrine system, which is the body’s second important regulating system, the
nervous system is able to constantly regulate and maintain homeostasis within narrow limits. This
chapter looks at both the structural and functional classifications of the nervous system, first
separately and then as an integrated whole, to help students conceptualize the complexity of this
system.
First, this chapter describes the structure and function of nervous tissue. The types
and activities of the supporting cells are discussed, followed by a complete description of the anatomy
of a neuron. Neurons are then classified as either afferent (sensory), efferent (motor), or association
neurons, and the role of each type is presented. Discussion of the physiology of nerve impulses is
next, focusing on the two functional properties of neurons, irritability and conductivity. Both of these
properties are explored, and the mechanisms involved within simple and more complex reflex arcs are
explained to help clarify application of these principles.
The next section of the chapter presents the central nervous system and its components. The
structure and function of the cerebral hemispheres, diencephalon, brain stem, cerebellum, and spinal
cord are explored, followed by a discussion of the protection provided to the CNS by the meninges
and cerebrospinal fluid. A discussion of some of the more common brain dysfunctions showcases their
variability and provides interesting starting points for classroom discussions.
The final section of this chapter examines the peripheral nervous system, beginning with the
cranial and spinal nerves, followed by a discussion of the differences between the somatic and
autonomic nervous systems. The autonomic nervous system is then further subdivided into its
sympathetic and parasympathetic divisions, and the “fight-or-flight” mechanism of the sympathetic
division is compared to the “resting and digesting” mechanism of the parasympathetic division.
Finally, the developmental aspects of the nervous system are presented, along with a discussion of
some of the more common congenital complications, such as cerebral palsy and spina bifida.
SUGGESTED LECTURE OUTLINE
I.
ORGANIZATION OF THE NERVOUS SYSTEM (pp. 223–224)
A.
Structural Classification (p. 223)
1.
Central Nervous System (CNS)
a.
Brain
b.
Spinal cord
2.
Peripheral Nervous System (PNS)
a.
Nerves
b.
Ganglia
B.
Functional Classification (pp. 223–224)
1.
Sensory (Afferent) Division
2.
Motor (Efferent) Division
a.
Somatic Nervous System
b.
Autonomic Nervous System (ANS)
II.
III.
NERVOUS TISSUE: STRUCTURE AND FUNCTION (pp. 224–235)
A.
Supporting Cells (pp. 224–226)
1.
Astrocytes
2.
Microglia
3.
Ependymal
4.
Oligodendrocytes
B.
Neurons (pp. 226–235)
1.
Anatomy
a.
Axons—one per cell
b.
Dendrites—many per cell
2.
Classification
a.
Functional Classification
b.
Structural Classification
3.
Physiology
a.
Nerve Impulses
b.
Reflex Arcs
CENTRAL NERVOUS SYSTEM (pp. 235–249)
A.
Functional Anatomy of the Brain (pp. 235–241)
1.
Cerebral Hemispheres
a.
Surface (cortex)—grey matter
I.
Basal nuclei
b.
Interior—white matter
c.
Gyri
d.
Sulci
e.
Fissures
2.
Diencephalon
a.
Thalamus
b.
Hypothalamus
c.
Epithalamus
3.
Brain Stem
a.
Midbrain
b.
Pons
c.
Medulla Oblongata
d.
Reticular Formation
4.
Cerebellum
B.
Protection of the Central Nervous System (pp. 241–244)
1.
Bones of skull and vertebral column
2.
Meninges
a.
Dura mater—outermost
b.
Arachnoid matter—middle
c.
Pia mater—innermost
3.
Cerebrospinal Fluid (CSF)
a.
Choroid plexus—CSF formation
b.
CSF location
4.
The Blood-Brain Barrier
a.
Relatively impermeable capillaries
C.
Brain Dysfunctions (pp. 244–247)
1.
Traumatic Brain Injuries
a.
Concussions—reversible damage
b.
Contusions—nonreversible damage
2.
Cerebrovascular Accidents (CVA)—stroke
a.
Visual impairment
D.
IV.
V.
b.
Paralysis
c.
Aphasias
3.
Alzheimer’s Disease
4.
Huntington’s Disease
5.
Parkinson’s Disease
6.
Diagnosis (pp. 262–263)
a.
Electroencephalogram (EEG)
b.
Simple reflex tests
c.
Pneumoencephalography
d.
Angiography
e.
CT scans
f.
PET scans
g.
MRI scans
Spinal Cord (pp. 247–249)
1.
Gray Matter of the Spinal Cords and Spinal Roots
2.
White Matter of the Spinal Cord
PERIPHERAL NERVOUS SYSTEM (pp. 249–263)
A.
Structure of a Nerve (p. 249)
B.
12 Pairs of Cranial Nerves (pp. 249–253)
1.
Olfactory
2.
Optic
3.
Oculomotor
4.
Trochlear
5.
Trigeminal
6.
Abducens
7.
Facial
8.
Vestibulocochlear
9.
Glossopharyngeal
10.
Vagus
11.
Accessory
12.
Hypoglossal
C.
31 Pairs of Spinal Nerves and Nerve Plexuses (p. 253; Figure 7.22)
D.
Autonomic Nervous System (pp. 253–263; Table 7.3)
1.
Somatic and Autonomic Nervous Systems Compared
2.
Anatomy of the Parasympathetic Division
3.
Anatomy of the Sympathetic Division
4.
Autonomic Functioning
DEVELOPMENTAL ASPECTS OF THE NERVOUS SYSTEM (pp. 263–266)
A.
Embryonic Brain Development
1.
Cerebral palsy
2.
Anencephaly
3.
Hydrocephalus
4.
Spina bifida
B.
Premature Infants
1.
Temperature regulation via hypothalamus