Structure [edit]. Nervous tissue is composed of neurons, also called nerve cells, and neuroglial cells. Typically, nervous tissue is categorized into four types of tissue. In the central nervous system (CNS), the tissue types found are grey matter and white matter.In the peripheral nervous system (PNS), the tissue types are nerves and ganglia.ypically, nervous tissue is categorized into four types of tissue. In the central nervous system (CNS), the tissue types found are grey matter and white matter. In the peripheral nervous system (PNS), the tissue types are nerves and ganglia.