b. Nerve. A nerve is a collection of neuron processes together and outside of
c. Fiber Tract. A fiber tract is a collection of neuron processes together and
within the CNS.
d. Ganglion. A ganglion is a collection of nerve cell bodies together and
outside of the CNS.
e. Nucleus. A nucleus is a collection of nerve cell bodies together and within
f. General Versus Special. If a nervous element is found throughout the
body, it is said to be general. A nervous element located in just one part of the body,
such as the head, is said to be special. For example, there are general senses, such as
pain and temperature, and there are special sense organs, such as the eyes and the
g. Somatic Versus Visceral.
(1) The term somatic refers to the peripheral part of the body. Thus, when
we speak of somatic innervation, we are talking about the nerve supply to the trunk wall,
upper and lower members, head, and neck.
SOMA = body, body wall
(2) The term visceral refers to the visceral organs. These include hollow
organs with smooth muscle (such as the intestines and the blood vessels) as well as
sweat glands. Thus, visceral innervation refers to the nerve supply for these organs.
Note that the visceral organs are located within both the trunk and periphery of the
body. Those in the periphery include the blood vessels and the sweat glands.
OVERVIEW OF THE HUMAN NERVOUS SYSTEM
The human nervous system is an integrated, connected circuitry of nervous
a. It is supplied with special junctions called synapses. The synapses ensure
the flow of information along the circuitry in the proper direction.
b. In general terms, the human nervous system can be compared to a
computer. There is input--the sensory information. There is central collation of input
along with previously stored information.
COLLATE = collect, compare, and arrange in order