The key difference between microglia and macroglia is that microglia are the immune cells of the central nervous system that protect it against injuries and diseases while microglia are neuronal supportive cells which mainly provide nutrient support, maintain brain metabolism and homeostasis, and produce myelin sheath around axons.
Glial cells or neuroglia are the most abundant cell type present in the CNS. There are two types of glial cells as microglia and macroglia. Microglia are immune cells in the central nervous system. In fact, they are specialized macrophages that have the ability to perform phagocytosis and destroy pathogens. Macroglia help in the synthesis of myelin and provide adequate nutrition support to the nervous system. Macroglia cells include oligodendrocytes, astrocytes, ependymal cells, Schwann cells and satellite cells. They are found in both CNS and PNS.
CONTENTS
1. Overview and Key Difference
2. What are Microglia
3. What are Macroglia
4. Similarities Between Microglia and Macroglia
5. Side by Side Comparison – Microglia vs Macroglia in Tabular Form
6. Summary
What are Microglia?
Microglia are a type of neuroglia in the brain. They are immune cells derived from embryonic mesoderm. Therefore, they are the protective cells in the central nervous system. They are specialized macrophages.
Figure 01: Microglia
Microglia are the smallest glial cells with oval-shaped nuclei. They have slender, elongated processes which aid them to move via chemotaxis. Microglia are activated by the inflammation in the central nervous system. Then they act as macrophages and mediate immune responses in the central nervous system. These cells are involved in clearing cellular debris and dead neurons from the nervous tissue via phagocytosis.
What are Macroglia?
Macroglia are the second type of glial cells. There are three types of microglia in the central nervous system: astrocytes, oligodendrocytes, and ependymal cells. In the peripheral nervous system, there are two main types of microglia as Schwann cells and satellite cells. Astrocytes are the most common glial cells in the central nervous system. They are star-shaped cells that carry out several important functions, including the formation of blood brain barrier, regulation of chemicals around the brain, regulation of brain metabolism and homeostasis, the supply of food, water and ions from the periphery to the brain and synchronization of the activity of axons.
Oligodendrocytes are the neuroglia that synthesizes myelin sheath around the axons. Moreover, they secrete some growth factors to help neuronal growth and development. Myelin sheaths insulate the axons to prevent the loss of signals and to increase the rate of signal transmission. Ependymal cells are responsible for creating and secreting cerebrospinal fluid (CSF).
Figure 02: Types of Glia
Schwann cells synthesize myelin around the axons in the neurons of the peripheral nervous system. Moreover, Schwann cells act as immune cells in the PNS and involve in the clearing of cellular debris and re-growth of neurons in the PNS. Satellite cells regulate the external chemical environment in the PNS.
What are the Similarities Between Microglia and Macroglia?
- Both microglia and microglia are two major types of glial cells.
- They are non-neuronal cells in the nervous system.
- Moreover, they are neuronal supportive cells.
- They are not involved in the transmission of nerve impulses.
What is the Difference Between Microglia and Macroglia?
Microglia are immune cells in the central nervous system which act as macrophages and protect the brain from injuries and diseases. Macroglia are supportive cells which mainly provide nutrient support, maintain brain metabolism and homeostasis, and produce myelin sheath around axons. So, this is the key difference between microglia and microglia. Also, another significant difference between microglia and microglia is that the microglia are derived from embryonic mesoderm whilethe macroglia are derived from neuroectoderm.
Moreover, microglia are found only in the central nervous system while microglia are found in both the central and peripheral nervous system.
Below infographic tabulates more differences between microglia and microglia.
Summary – Microglia vs Macroglia
Neuroglia are non-neuronal supportive cells of the neurons in the nervous system. There are two types of neuroglia as microglia and macroglia. Microglia are immune cells in the central nervous system. They protect the central nervous system from injuries and diseases. Macroglia are neuronal supportive cells in both the central and peripheral nervous system. They are involved in several different functions, including the myelin synthesis, regulation of chemicals around the brain, re-growth of neurons, clearing of cellular debris and dead neurons, etc. Thus, this summarizes the difference between microglia and microglia.
Reference:
1. “Types of Glia.” Queensland Brain Institute, 16 June 2017, Available here.
2. “Glia.” Wikipedia, Wikimedia Foundation, 27 July 2020, Available here.
Image Courtesy:
1. “Mikroglej 1” By GrzegorzWicher~commonswiki assumed (based on copyright claims). – Own work assumed (based on copyright claims)., Public Domain) via Commons Wikimedia
2. “Blausen 0870 TypesofNeuroglia” By Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work (CC BY 3.0) via Commons Wikimedia