LESSON 11
THE HUMAN NERVOUS SYSTEM
Section I. INTRODUCTION
11-1. NERVOUS TISSUES
There are two types of nervous tissues--the neurons (nerve cells) and glia
(neuroglia). See paragraph 2-17. The neuron is the basic structural unit of the nervous
system. The glia are cells of supporting tissue for the nervous system. There are
several different types of glia, but their general function is support (physical, nutritive,
etc.).
11-2. SPECIALIZATION
Nervous tissues are specialized to:
a. Receive Stimuli. Cells receiving stimuli are said to be "irritable" (as are all
living cells to a degree).
b. Transmit Information.
c. "Store" Information. The storing of information is called memory.
Section II. THE NEURON AND ITS "CONNECTIONS"
11-3. DEFINITION
A neuron (figure 11-1) is a nerve cell body and all of its processes (branches).
11-4. NEURON CELL BODY
The neuron cell body is similar to that of the "typical" animal cell described in
lesson 1.
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11-3