Nervous System - (Oligodendrocytes, Microglia, Ependymal, Schwann cells & Satellite cells)

• resemble astrocytes; smaller and contain fewer processes

Oligodendrocytes

• responsible for forming and maintaining the myelin sheath around CNS axons

Oligodendrocyte processes

• multilayered lipid and protein covering

• insulates some axons and increases the speed nerve impulse conduction. (such axons are said to be myelinated)

myelin sheath

• are small cells with slender processes ; give off numerous spine-like projections

• they remove cellular debris formed during normal development of the nervous system and phagocytize microbes and damaged nervous tissue.

• act as phagocytes

microglia

• cuboidal to columnar cells ; arranged in a single layer ; microvilli and cilia

• These cells line the ventricles of the brain and central canal of the spinal cord

Ependymal cells

function of ependymal cells

• produce, monitor and assist in the circulation of cerebrospinal fluid

• form the blood - cerebrospinal fluid barrier

the neuroglia of the _____ surround axons and cell bodies.

PNS

• encircle PNS axons

• Like oligodendrocytes, they form the myelin sheath around axons

• participate in axon regeneration

Schwann cells

a single oligodendrocytes myelinates ___(1)___, while a Schwann cell myelinates a __(2)__

1. several axons

2. single axon

the axon regeneration is ______.

more easily accomplished in the PNS than in CNS.

A single Schwann cell can enclose how many unmyelinated axons?

20 or more

• flat cells ; surround the cell bodies of neurons in the PNS ganglia

• besides providing support, they regulate the exchanges of materials between neuronal cell bodies and interstitial fluid

Satellite cells