Final answer:
Supporting cells in the nervous system have specific roles, including myelin production by oligodendrocytes (CNS) and Schwann cells (PNS), regulation of the extracellular environment and the blood-brain barrier by astrocytes, immune defense by microglia, and production of cerebrospinal fluid by ependymal cells.
Step-by-step explanation:
The supporting cell types of the nervous system each have distinct functions:
- Oligodendrocytes: Produce myelin in the central nervous system (CNS), insulating axons to facilitate rapid signal transmission.
- Schwann cells: Similar to oligodendrocytes, but they produce myelin in the peripheral nervous system (PNS), with each cell myelinating a single axon.
- Astrocytes: Provide structural support, regulate the extracellular environment, maintain the blood-brain barrier, and provide nutrients to neurons. They also are involved in the repair and scarring process of the brain and spinal cord.
- Microglia: Act as the primary immune defense in the CNS, performing phagocytosis to engulf and digest cellular debris, foreign substances, and pathogens.
- Ependymal cells: Line the ventricles of the brain and the spinal cord, producing and circulating cerebrospinal fluid which cushions the brain and may also play a role in directing neuronal migration during brain development.