Table 1:

Cell types within the central nervous system

Cell Types		Description
Neuron		Primary cell type within the central nervous system (CNS) and peripheral nervous system (PNS) distinct from other cell types due to their electrical excitability. Responsible for receiving, processing and transmitting electrical and chemical signals. A typical neuron consists of a cell body (soma), dendrites and an axon.
Neuroglia		Non-neuronal cells within the peripheral and central nervous system.
•Macroglia		Cells derived from the ectoderm.
CNS	○Astrocytes	Most abundant macroglia in the CNS. Provide a vascular supply to neurons and in doing so form an important part of the blood brain barrier. They affect potassium influx and efflux and influence neurotransmitters to regulate the external environment of neurons.
	○Oligodendrocytes	These cells create the ‘myelin sheath’; a protective coating around the axon which enables effective propagation of electrical impulses along the neuron. In addition they provide trophic support by the production of glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), or insulin-like growth factor-1 (IGF-1).
	○Ependymal cells	These cells whch comprise the blood-CSF barrier line the ventricular system and spinal cord and producing cerebrospinal fluid and enabling its flow throughout the CNS.
PNS	○Schwann cells	Responsible for the production of the myelin sheath in peripheral nerve axons are known to have phagocytic properties which allows for ongoing production of PNS neurons.
	○Satellite cells	These cells comprise sensory, parasympathetic and sympathetic ganglia and are responsible for regulation of the external chemical environment.
	○Enteric glial cells	Within the intrinsic ganglia of the digestive system these cells contribute to regulation of the enteric system.
•Microglia		Located within the brain and spinal cord these cells are the resident macrophages within the CNS.