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Biology · Glossary

What is Nervous tissue?

Also known as: neuron · glial cell

Definition 4.11 University Biology — Year 1 · Chapter 4 — Animal Body Plans and Tissues

Nervous tissue is made of neurons, cells with a body and long extensions (dendrites receiving signals, an axon carrying them away) that conduct electrical signals and pass them to other cells at synapses, and of glial cells, several times more numerous, which support, insulate and feed the neurons. It senses, integrates and commands.

The four tissue types under the microscope. Top left: simple columnar epithelium, a single row of tall cells. Top right: loose connective tissue, scattered cells among wavy collagen fibres. Bottom left: skeletal muscle fibres, striated, with nuclei at their edges. Bottom right: a neuron among glial cells.
The four tissue types under the microscope. Top left: simple columnar epithelium, a single row of tall cells. Top right: loose connective tissue, scattered cells among wavy collagen fibres. Bottom left: skeletal muscle fibres, striated, with nuclei at their edges. Bottom right: a neuron among glial cells.

Examples

Example 4.12 (Where the tissues come from)

Epithelia derive from all three germ layers (skin from ectoderm, gut lining from endoderm, the lining of vessels and of the coelom from mesoderm); connective tissue, muscle and blood from mesoderm; nervous tissue from ectoderm. The frog’s skin is an ectodermal epithelium on mesodermal connective tissue; its gut, an endodermal epithelium wrapped in mesodermal muscle; its brain, ectoderm folded inward.

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