Neuroglia of the CNS

Astrocytes functions: Creating 3 dimensional framework for CNS

Astrocytes are packed with microfilaments that extend across the breadth of the cell=mechanical strength and astrocytes form structural framework supporting neurons of brain and spinal cord.

name four types of neuroglia

Astrocytes, oligodendrocytes, microglia and ependymal cells.

Oligodendrocytes function

Myelinates CNS axons; provides structural framework

What is grey matter?

Regions dominated by neuron cell bodies, dendrites and unmyelinated axons. =dark grey dusky color

Summary of function of Microglia

Remove cell debris, wastes and pathogens by phagocytosis.

Astrocytes functions: Guiding neuron development

in embryonic brain, astrocytes are involved in directing growth and interconnection of developing neurons via secretion of chemicals called neurotropic factors.

Oligodendrocytes: myelin sheath gaps

small gaps (nodes of ranvier) exist between myelin sheath produced by adjacent oligodendrocytes

Microglia composition

smallest of glial cells slender cytoplasmic processes with many fine branches (microglia cells)

Oligodendrocytes processes

usually contact axons and cell bodies of neurons. tie axons together improve functional performance of neurons by wrapping axon in myelin (material with insulating properties)

Ependymal cells: where are they found?

Ventricles of the brain and central canal of spinal cord. (ependyma)

Function of Microglia

act as roving security system. phagocytic cells of CNS. Engulf cellular debris and waste products. Protect CNS by phagocytosing viruses, microorganisms and tumor cells. in times of infection or injury % increases.

Microglia lowdown

appear in embryonic development through division of mesodermal stem cells. these stem cells also related to produce tissue macrophages and monocytes of blood. migrate to CNS =remain in neural tissue.

Astrocytes functions: Performing repairs in damaged neural tissue

astrocytes make structural repairs that stabilize tissue and prevent further injury via scar tissue.

Ependymal cells composition with CSF

chamber and passageways filled with cerebral spinal fluid (CSF). fluid provides protective cushion, and transports dissolved gases, nutrients, wastes and other materials. Cuboidal, slender processes branch extensively and make direct contact with glial cells in surrounding neural tissue. free surfaces covered in cilia (may assist in circulation of CSF)

Astrocytes (largest amount of glial cells)

controlling interstitial environment, maintaining the blood brain barrier, creating three dimensional framework for CNS, performing repairs in damaged neural tissues and guides neuron development.

Astrocytes functions: Controlling interstitial environment

large amounts of cytoplasmic processes which increase surface area, which facilitate scavenging of ions, neurotransmitters or metabolic by-products. Exchange of ions and etc. with extracellular fluid enables astrocytes to control chemical content of interstitial environment of CNS.

Ependymal cells function

line ventricle (brain and central canal); assist in producing, circulating and monitoring cerebrospinal fluid

Astrocytes functions: Maintaining blood brain barrier

neural tissue is physically and biochemically isolated from general circulation. hormones or other chemicals in blood can disrupt neuron function. Endothelial cells lining CNS capillaries are responsible for blood brain barrier. Control chemical exchange between blood and interstitial fluid. Cytoplasmic blanket only interfered when other glial cells contact capillary walls.

what is white matter?

regions dominated by myelinated axons of CNS =appear glossy white

Oligodendrocytes: Internodes

relatively large areas wrapped in myelin sheath

Oligodendrocytes composition

resemble astrocytes only in that they both have smaller cell bodies and fewer shorter cytoplasmic processes.