13.4: Glia (Neuroglia) Cells
- Page ID
- 53710
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Glia (Neuroglia) Cells
Above: Illustrations of the six types of glia cells. Ependymal cells, oligodendrocytes, astrocytes, and microglia are found in the CNS only. Satellite cells and
Schwann cells are found in the PNS only. Both oligodendrocytes and Schwann cells wrap around axons of neurons forming myelin sheaths. Both astrocytes and satellite cells protect cell bodies from chemicals found in other tissues such as the blood. Ependymal cells protect neurons by producing cerebrospinal fluid (CSF). Microglia protect neurons by removing debris from nervous tissue.
Neurons are central to the functionality of the nervous system since they carry signals, thereby enabling collection of sensory information, processing of information, and transmission of motor commands. However, neurons are sensitive cells that need protection and support from glia cells. Examine the table below describing the six different types of glia cells, their functions, and whether they are found in the CNS or in the PNS.
|
Glia Cells |
Function |
Cells in CNS |
Cells in PNS |
|---|---|---|---|
|
oligodendrocytes, Schwann cells |
cells that wrap axons in myelin sheaths (glial membrane extensions) that increase action potential velocity |
oligodendrocytes (one cell branches to wrap around multiple axons) |
Schwann cells (one cell wraps around one axon segment) |
|
astrocytes, satellite cells, ependymal cells |
cells that form borders between nervous tissues and other body tissues (protection) |
astrocytes ependymal cells (make CSF) |
Satellite cells |
|
microglia |
immune cells that clear cellular debris from nervous tissues |
microglia |
-- |
Above: Diagram above shows the four types of glia cells of the central nervous system with neurons. Oligodendrocytes have multiple branches to myelinate multiple axon segments. Astrocytes wrap around blood vessels to protect neurons from substances that might interfere with neuron function. Microglia are mobile and patrol around nervous tissue to remove debris. Ependymal cells line the ventricles in the brain and the central canal in the spinal cord to create cerebrospinal fluid (CSF)
Above: (Bottom) Diagram showing Schwann cells wrapped around the axon of a neuron in the PNS. Schwann cells create myelin sheaths insulating the axon to increase the rate of propagation of an action potential. A cross section of the Schwann cell with its axon segment shows that the Schwann cell coils around the axon with its nucleus at a peripheral location. (Top) Microscopic image of axons (red) within a nerve (in the PNS). Wrapped around the axons are Schwann cells (green) creating myelin sheaths. The nuclei of Schwann cells are shown in blue.
Attributions
- "Blausen 0870 TypesofNeuroglia.png" by BruceBlaus is licensed under CC BY 3.0
- "Glial Cell Types.png" by Holly Fischer is licensed under CC BY 3.0
- "Principles of Biology I and II lab manuals" by Dalton State University is licensed under CC BY-SA 4.0
- "Propagation of action potential along myelinated nerve fiber en.svg" by Helixitta is licensed under CC BY-SA 4.0