Nerve

Learning objectives

  • Know the components of tissue in the central and peripheral nervous systems.
  • Understand the meaning of terms gray matter and white matter.
  • Relate nerve function to the properties of neurons and their cell processes: axons and dendrites.

The central nervous system (CNS) includes:

  1. nerve cells (neuronal cell bodies) and their dendrites and axons (both myelinated and unmyelinated),
  2. supporting cells, (the neuroglia): oligodendroglia, astrocytes and microglia
  3. meninges: dura, arachnoid, and pia,
  4. blood vessels.

The peripheral nervous system (PNS) contains:

  1. neurons (organized into clusters called ganglia),
  2. supporting cells including satellite cells associated with the ganglionic neurons and schwann cells which form the myelin sheath
  3. connective tissue elements (endoneurium, perineurium and epineurium)
  4. blood vessels.

The neuron is the structural and functional unit of the nervous system. Neurons are highly polarized cells. The cell body contains the nucleus and synthetic apparatus. The highly branched dendrites are the receptive pole and axons are the transmitting pole. Nervous tissue is characterized by its extreme specialization for excitability and conductivity.

The supporting cells are in intimate contact with the neurons and their processes in both the CNS and the PNS. These cells provide structural support and nutrients to the neurons. There are also macrophages present in the nervous system; these cells are called microglia in the CNS.

The connective tissue elements include the meninges, which surround the central nervous system; capsules surround some sense organs and ganglia; and the endo-, peri-, and epineurium of peripheral nerves.

The detailed structure and function of the nervous system will be studied during the neurosciences course. The following class slides and electron micrographs will serve to acquaint you with nervous tissue as one of the four basic tissues.

Lab activities

  1. Central Nervous System
  2. Brain
  3. Peripheral Nervous System
  4. Enteric Nervous System
  5. Peripheral Nervous System: Peripheral Nerves
  6. Electron Micrographs