glial cell

Examples of glial cell in the following topics:

• Glia

  • While glia (or glial cells) are often thought of as the supporting cast of the nervous system, the number of glial cells in the brain actually outnumbers the number of neurons by a factor of ten.
  • Neurons would be unable to function without the vital roles that are fulfilled by these glial cells.
  • Glial cells support neurons and maintain their environment.
  • Glial cells of the (a) central nervous system include oligodendrocytes, astrocytes, ependymal cells, and microglial cells.
  • (a) Astrocytes and (b) oligodendrocytes are glial cells of the central nervous system.

• Clusters of Neuronal Cell Bodies

  • Ganglia are composed mainly of neuron cell bodies (somata) and dendritic structures.
  • Satellite glial cells are a type of glial cell that line the exterior surface of neurons in the peripheral nervous system (PNS) .
  • Satellite glial cells (SGCs) also surround neuron cell bodies within ganglia.
  • Satellite cells also act as protective, cushioning cells.
  • Satellite glial cells are expressed throughout the sympathetic and parasympathetic ganglia in their respective nervous system divisions.

• Muscle Tissues and Nervous Tissues

  • A nerve consists of a neuron and glial cells.
  • Glial cells support the neurons.
  • Other glial cells support the nutritional and waste requirements of the neuron.
  • Some of the glial cells are phagocytic, removing debris or damaged cells from the tissue.
  • Also shown are two types of glial cells: astrocytes to regulate the chemical environment of the nerve cell, and oligodendrocytes to insulate the axon so the electrical nerve impulse is transferred more efficiently.

• Types of Nervous Tissue

  • Neuroglia are also called "glial cells."
  • These glial cells are involved in many specialized functions apart from support of the neurons.
  • In the PNS, satellite cells and Schwann cells are the two kinds of neuroglia.
  • Astrocytes are shaped like a star and are the most abundant glial cell in the CNS.
  • Satellite cells surround neuron cell bodies in the peripheral nervous system (PNS).

• Neuroglia of the Peripheral Nervous System

  • There are two kinds of glia cells in the PNS - schwann cells and satellite cells which have unique functions.
  • There are two kinds of neuroglia in the PNS - Schwann Cells and Satellite cells.
  • Schwann cells provide myelination to peripheral neurons.
  • Functionally the schwann cells are functionally similar to oligodendrocytes of the CNS.
  • Satellite glial cells are small glia that surround neurons' sensory ganglia in the ANS.

• Introducing the Neuron

  • Neurons are specialized cells that transmit chemical and electrical signals.
  • The brain is made up entirely of neurons and glial cells, which are non-neuronal cells that provide structure and support for the neurons.
  • The cell body contains a specialized structure, the axon hillock, which serves as a junction between the cell body and the axon.
  • Myelin is produced by glial cells (or simply glia, or "glue" in Greek), which are non-neuronal cells that provide support for the nervous system.
  • In the central nervous system, the glial cells that form the myelin sheath are called oligodendrocytes; in the peripheral nervous system, they are called Schwann cells.

• Neuroglia of the Central Nervous System

  • Neuroglia in the CNS include astrocytes, microglial cells, ependymal cells and oligodendrocytes.
  • Astrocytes are star shaped delicate branching glial cells.
  • Ependymal cells are another glial subtype that line the ventricles of the CNS.
  • Oligodendrocytes are cells that have fewer processes compared to astrocytes.
  • Oligodendrocytes form the electrical insulation around the axons of CNS nerve cells.

• Neurons and Glial Cells

  • Instead, they have a system of separate-but-connected nerve cells (neurons) called a "nerve net."
  • Echinoderms, such as sea stars, have nerve cells that are bundled into fibers called nerves.
  • Although glial cells support neurons, recent evidence suggests they also assume some of the signaling functions of neurons.
  • (a) In cnidarians, nerve cells form a decentralized nerve net.
  • (b) In echinoderms, nerve cells are bundled into fibers called nerves.

• Organization of the Nervous System

  • The nervous system is a network of cells called neurons that coordinate actions and transmit signals between different parts of the body.
  • Central to the functioning of the nervous system is an extensive network of specialized cells called neurons.
  • Neurons send signals along thin fibers called axons and communicate with other cells by releasing chemicals called neurotransmitters at cell-cell junctions called synapses .
  • Along with neurons, the nervous system relies on the function of other specialized cells called glial cells, or glia, that provide structural and metabolic support to the nervous system.
  • When this signal reaches a synapse, it provokes release of neurotransmitter molecules, which bind to receptor molecules located in the the target cell.

• Capacity of Different Tissues for Repair

  • Neuroregeneration refers to the regrowth or repair of nervous tissue, cells, or cell products.
  • It is limited by the inhibitory influences of the glial and extracellular environment.
  • Glial scars rapidly form, and the glia actually produce factors that inhibit remyelination and axon repair.
  • All of these factors contribute to the formation of what is known as a glial scar, which axons cannot grow across .
  • Astrocytes can be identified in culture because, unlike other mature glia, they express glial fibrillary acidic protein.