Main Difference – Schwann cell vs Oligodendrocyte
Schwann cell and oligodendrocyte are two types of glial cells found in the nervous system. The glial cells and nerve cells are the two types of cells found in the nervous system. Both of the cells are wrapped around the axons of the nerve cells. The axons carry nerve impulses away from the cell body of the neuron. The main difference between Schwann cell and oligodendrocyte is that Schwann cell is wrapped around the axons of the nerve cells found in the peripheral nervous system whereas oligodendrocyte is wrapped around the axons of the nerve cells found in the central nervous system. Schwann cells can wrap around only a single axon. In contrast, oligodendrocytes can wrap around axons of up to 50 nerve cells.
Key Areas Covered
1. What is a Schwann Cell
– Definition, Characteristics, Function
2. What is an Oligodendrocyte
– Definition, Characteristics, Function
3. What are the Similarities Between Schwann Cell and Oligodendrocyte
– Outline of Common Features
4. What is the Difference Between Schwann Cell and Oligodendrocyte
– Comparison of Key Differences
Key Terms: Axons, Central Nervous System (CNS), Insulation, Myelin, Nerve cells, Neural Crest, Neurilemma Cells, Oligodendrocyte, Oligodendrocyte Precursor Cells (OPCs), Peripheral Nervous System (PNS), Schwann Cell
What is a Schwann Cell
A Schwann cell is a type of glial cells found in the peripheral nervous system (PNS) of higher vertebrates. Schwann cells are also called the neurilemma cells. The other types of glial cells in the PNS are astrocytes, microglia, and ependymal cells. The main function of the Schwann cells is to insulate the axons of the nerve cells in the PNS. Schwann cells develop from the neural crest cells. The two types of Schwann cells are myelinated Schwann cells and non-myelinated Schwann cells. Both types of Schwann cells are important in the maintenance and regeneration of axons of the nerve cells in PNS. Myelin is a white color, fatty substance, which serves as an electrically insulating layer on the axon of nerve cells. Therefore, myelination decreases the membrane capacitance of the axons, allowing a salutatory conduction. Most of the times, the non-myelinated Schwann cells are important in the maintenance of axons. Furthermore, they are vital for the survival of the neurons.
Figure 1: Schwann Cells
Schwann cells are mediated by the transcription factors such as Oct-6, Krox-20, and Sox-10. The Guillain–Barré Syndrome and the Charcot–Marie-Tooth disease are types of demyelinating disorders in the Schwann cells. The colonization of Mycobacterium leprae in the Schwann cell cause the disease called leprosy. The Schwann cells can be used as therapeutic agents in demyelinating diseases as well as in spinal cord injuries. The Schwann cells in a peripheral nerve cell are shown in figure 1.
What is an Oligodendrocyte
An oligodendrocyte is a type of glial cells found in the central nervous system (CNS). The other types of glial cells are the satellite glial cells in ganglia. The main function of the oligodendrocytes is the insulation of the axons of the nerve cells in the CNS. Oligodendrocytes are composed of several cytoplasmic projections. Therefore, a single cell can be wrapped around several axons. All oligodendrocytes are myelinated. Therefore, the time taken for the signal transduction through the axon is decreased. Since myelin is a white color substance, it forms the white matter in the brain. But, some oligodendrocytes can be found in the gray matter as well. The myelinated surfaces on the axons are called internodes. The non-myelinated surfaces of the axon are called the node of Ranvier.
Figure 2: Oligodendrocyte
The oligodendrocytes are derived from the oligodendrocyte progenitor cells (OPCs). The proliferation of the OPCs is induced by platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF). An oligodendrocyte wrapped around several axons is shown in blue color in figure 2.
Similarities Between Schwann Cell and Oligodendrocyte
- Schwann cells and oligodendrocytes are two types of glial cells found in the nervous system of higher vertebrates.
- The main function of both Schwann cells and oligodendrocytes is to insulate the axons of the nerve cells.
- Both Schwann cells and oligodendrocytes are capable of forming myelin sheaths around the axons.
- Both Schwann cells and oligodendrocytes facilitate the signal transduction through the axons.
Difference Between Schwann Cell and Oligodendrocyte
Definition
Schwann Cell: A Schwann cell is a glial cell that is wrapped around an axon of the nerve cells in the peripheral nervous system.
Oligodendrocyte: An oligodendrocyte is a glial cell with several slender processes, which is wrapped around the axons of the nerve cells in the central nervous system.
Derived from
Schwann Cell: Schwann cells are derived from the neural crest.
Oligodendrocyte: Oligodendrocytes are derived from the oligodendrocyte precursor cells.
Insulating Axons
Schwann Cell: Schwann cells insulate the axons of the nerve cells in the peripheral nervous system.
Oligodendrocyte: Oligodendrocytes insulate the nerve cells in the central nervous system.
Number of Insulating Axons
Schwann Cell: Schwann cells are capable of insulating only a single axon.
Oligodendrocyte: Oligodendrocytes are capable of insulating up to 50 different axons at once.
Myelination
Schwann Cell: Schwan cells can be myelinated or non-myelinated.
Oligodendrocyte: All oligodendrocytes are myelinated.
Cytoplasmic Projections
Schwann Cell: Schwann cells do not consist of cytoplasmic projections.
Oligodendrocyte: Oligodendrocytes consist of cytoplasmic projections.
Diseases
Schwann Cell: The diseases associated with Schwann cells are the Guillain–Barré Syndrome, the Charcot–Marie-Tooth disease, and leprosy.
Oligodendrocyte: The diseases associated with oligodendrocytes are spinal cord trauma, multiple sclerosis, cerebral palsy, and leukodystrophies.
Conclusion
Schwann cell and oligodendrocyte are two types of glial cells found in the nervous system. Both types of cells have the same function, insulating the axons of the nerve cells. Both types of the cells can be myelinated. Since myelin is capable of electrically insulating the axon, the nerve impulses can migrate only through the nodes of Ranvier. Therefore, the time taken to the signal transduction is reduced. The difference between Schwann cells and oligodendrocytes lies on the type of nerve cell axons they insulate. Schwann cells insulate the axons of the nerve cells in the PNS whereas oligodendrocytes insulate the nerve cells in the CNS.
Reference:
1. “Schwann cells: Origins and role in axonal maintenance and regeneration.” ScienceDirect, Available here. Accessed 21 Aug. 2017.
2. Bradl, Monika, and Hans Lassmann. “Oligodendrocytes: biology and pathology.” Acta Neuropathologica, Springer-Verlag, Jan. 2010, Available here. Accessed 21 Aug. 2017.
Image Courtesy:
1. “Neuron” (CC BY-SA 3.0) via Commons Wikimedia
2. “Oligodendrocyte illustration” By Artwork by Holly Fischer – (CC BY 3.0) via Commons Wikimedia
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