Nervous Tissue
The components of nervous tissue are specialized for the conduction of electrical impulses, which allow communication among other tissue types. The major structural and functional "unit" of nervous tissue is the nerve cell called neuron. Each neuron is composed of a cell body containing a nucleus and one or more long cytoplasmic extensions known as fibres. Highly branched fibres, called dendrites, bring impulses toward the cell body, while a single, unbranched fibre, the axon, carries information away from the cell body (Figure 17). The overall length of a neuron, including dendrites, cell body and axon, may vary from less than two centimeters to a meter or more.
Examine slide #23, a cross-section of the spinal cord. The central dark H-shaped region is the grey matter and the surrounding lighter-stained area is the white matter (Figure 18). Neuron’s cell bodies are the predominant structural elements of the grey matter whereas nerve fibres, especially axons, are the main component of the white matter.
Examine the grey matter of the spinal cord. The large cell bodies of the neurons should be evident in this area. The dendrites and axon of a particular neuron are only apparent at their junction with the cell body. (NOTE: You cannot distinguish between axons and dendrites in this particular area).
Figure 17: Neuron.
Figure 18A: Cross section of the spinal cord showing the location of the white and grey matter.
Spinal Cord XS.
Figure 18B: Microscopic view of cell bodies.
Close up of neuron.
What is the specific function of the nervous tissue?
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Give locations of the nervous tissue in the human body.
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