Nervous tissue

Nervous tissue

Example of nervous tissue

Cells of nervous tissue

Anatomical terminology

Nervous tissue or Nerve tissue is the main tissue component of the two parts of the nervous system; the brain and spinal cord of the central nervous system (CNS), and the branching peripheral nerves of the peripheral nervous system (PNS), which regulates and controls bodily functions and activity. It is composed of neurons, or nerve cells, which receive and transmit impulses, and neuroglia, also known as glial cells or more commonly as just glia (from the Greek, meaning glue), which assist the propagation of the nerve impulse as well as providing nutrients to the neuron.

Nervous tissue is made up of different types of nerve cells, all of which have an axon, the long stem-like part of the cell that sends action potential signals to the next cell. Bundles of axons make up the nerves.

Functions of the nervous system are sensory input, integration, control of muscles and glands, homeostasis, and mental activity.


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. The tissue is categorized by its neuronal and neuroglial components.[1]


Neurons are cells with specialized features that allow them to receive and facilitate nerve impulses, or action potentials, across their membrane to the next neuron.[2] They possess a large cell body (soma,perikaryon,cyton), with cell projections called dendrites and an axon. Dendrites are thin, branching projections that receive electrochemical signaling (neurotransmitters) to create a change in voltage in the cell. Axons are long projections that carry the action potential away from the cell body toward the next neuron. The bulb-like end of the axon, called the axon terminal, is separated from the dendrite of the following neuron by a small gap called a synaptic cleft. When the action potential travels to the axon terminal, neurotransmitters are released across the synapse and bind to the post-synaptic receptors, continuing the nerve impulse.[3]

Neurons are classified both functionally and structurally.

Functional classification:[4]

Structural classification:[4]

Neuroglia encompasses the non-neural cells in nervous tissue that provide various crucial supportive functions for neurons. They are smaller than neurons, and vary in structure according to their function.[3]

Neuroglial cells are classified as follows:[5]

Classification of Tissue

In the Central Nervous System:[10]

In the Peripheral Nervous System:[11]

The three layers of connective tissue surrounding each nerve are:[10]


Myelinated axons conduct impulses faster than unmyelinated axons.

The function of nervous tissue is to form the communication network of the nervous system by conducting electric signals across tissue.[12] In the CNS, grey matter, which contains the synapses, is important for information processing. White matter, containing myelinated axons, connects and facilitates nerve impulse between grey matter areas in the CNS.[13] In the PNS, the ganglion tissue, containing the cell bodies and dendrites, contain relay points for nerve tissue impulses. The nerve tissue, containing myelinated axons bundles, carry action potential/nerve impulses.[10]

Clinical significance


Neoplasms (tumours) in nervous tissue include:

Gliomatosis cerebri, Oligoastrocytoma, Choroid plexus papilloma, Ependymoma, Astrocytoma (Pilocytic astrocytoma, Glioblastoma multiforme), Dysembryoplastic neuroepithelial tumour, Oligodendroglioma, Medulloblastoma, Primitive neuroectodermal tumor
Ganglioneuroma, Neuroblastoma, Atypical teratoid rhabdoid tumor, Retinoblastoma, Esthesioneuroblastoma
Neurofibroma (Neurofibrosarcoma, Neurofibromatosis), Schwannoma, Neurinoma, Acoustic neuroma, Neuroma


  1. "Peripheral Nervous System". Histology and Virtual Microscopy Learning Resource. University of Michigan Medical School. Retrieved 29 January 2015.
  2. Byrne, John; Roberts, James (2004). From Molecules to Networks. California: Academic Press. p. 1. Check date values in: |access-date= (help);
  3. 1 2 Swenson, Rand. "Review of Clinical and Functional Neuroscience". Dartmouth Medical School. Retrieved 30 January 2015.
  4. 1 2 3 4 Waymire, Jack. "Organization of Cell Types". Neuroscience Online. The University of Texas Medical School. Retrieved 27 January 2015.
  5. 1 2 Verkhratsky, Alexi; Butt, Arthur (2013). Glial Physiology and Pathaphysiology (PDF) (First ed.). Chinchester, UK: John Wiley & Sons. p. 76. Retrieved 27 January 2015.
  6. Brodal, Per (March 1, 2010). The Central Nervous System: Structure and Function (Fourth ed.). Oxford University Press. p. 19. Retrieved 27 January 2015.
  7. Sofroniew, Michael; Vinters, Harry (2009). "Astrocytes: biology and pathology". Acta Neuropathol. 119 (1): abstract. doi:10.1007/s00401-009-0619-8. PMC 2799634Freely accessible. PMID 20012068.
  8. M, Hanani (2010). "Satellite glial cells in sympathetic and parasympathetic ganglia: in search of function". Brain Research Review. 64 (2): 1. doi:10.1016/j.brainresrev.2010.04.009. PMID 20441777. Retrieved 27 January 2015.
  9. Gershon, Michael; Rothman, Taube (1991). "Enteric Glia". Department of Anatomy and Cell Biology. 4: 195–204. doi:10.1002/glia.440040211.
  10. 1 2 3 "Neurons and Support Cells". SIU Med. Southern Illinois University School of Medicine. Retrieved 31 January 2015.
  11. "Cellular Components of Nervous Tissue" (PDF). RMC faculty. Randolph-Macon College. Retrieved 20 January 2015.
  12. "Nervous Tissue". Sidwell School. Retrieved 27 January 2015.
  13. Robertson, Sally. "What is Grey Matter". News Medical. AZo Network. Retrieved 30 January 2015.
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