Nonneuronal Cells of the Nervous System Melissa Metzler

Glial Cells  Make up about 90% of the cells in the nervous system but only 50% of the volume.  Cannot generate or transmit nerve signals.  They are responsible for the physical and metabolic support of the neurons.

Types of Nonneuronal Cells  Four types associated with the central nervous system. Astrocytes, oligodendrocytes, microglia, and ependymal cells Astrocytes, oligodendrocytes, microglia, and ependymal cells  Two types associated with the peripheral nervous system Satellite cells and Schwann cells. Satellite cells and Schwann cells.

Astocytes  Star-shaped cell that provides glucose and removes ammonia from the neurons.  Also regulates potassium and neurotransmitters around synapses. ysiology.htm

Astrocytes Continued…  Form a barrier around the blood vessels in the brain (blood-brain barrier). Keeps certain substances from moving into the brain. Keeps certain substances from moving into the brain.  Helps to direct neurons during embryo development and supplies the neurons with growth factors. winter2002/gallery.html

Oligodendrocytes and Microglia  Oligodendrocytes wrap extension of their cell membranes around sections of the axon (myelin sheaths). Myelin sheaths help to transmit nerve impulses. Myelin sheaths help to transmit nerve impulses.  Microglia remove pathogens and cell debris from the brain.

Ependymal Cells  Lines the ventricles or hollow spaces of the central nervous system and secretes cerebrospinal fluid Cerebrospinal fluid acts as a shock absorber and helps to carry nutrients to the cells. Cerebrospinal fluid acts as a shock absorber and helps to carry nutrients to the cells. outhwest.tn.e du/rburkett/A &P1_nervous _system_lab. htm

Nonneuronal Cells of the Peripheral Nervous System  Satellite cells protect the cells of the ganglia  Schwann cells form a myelin sheath around a segment of an axon. nervous_system.html

References 1. Pasternak, Jack J. An Introduction to Human Molecular Genetics: Mechanisms of Inherited Diseases. Second Edition. John Wiley & Sons, Inc Widmaier, Eric P.; Hershel, Raff; Strang, Kevin T. Vander’s Human Physiology: The Mechanisms of Body Functions. Tenth Edition. Mcgraw-Hill