Nervous System -nsu

Histology 5b Craig Clifford Northeastern State University Spring 2009

Nerve Tissue and the Nervous System  

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100 million nerve cells or neurons Each with an average 1000 connections with other neurons Organized in circuits and groups of circuits that carry out higher order neural function

Nervous System 

Central nervous system  

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Brain Spinal cord

Peripheral nervous system  

Nerve cells Ganglia

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There are two types of cells that make up the nervous system. 

Nerve cells or neurons 

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Usually with numerous long processes

Glial cells (Gr. glia, glue    

Short processes Support and protect neurons Neural nutrition Neural tissue defense

Neural development

Neurons   

Soma/cell body/perikaryon Dendrites Axon 

Terminal arborizations 

End bulbs/boutons

Types of neurons 

By function   

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Sensory/afferent Motor/efferent Interneurons/association neurons

By structure   

Multipolar Bipolar Pseudounipolar

Grey vs. white matter

White

Grey

Cell body 

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Trophic center of the cell exclusive of the dendrites and axon Nissl bodies = ribosomes and ER Golgi complex

Franz Nissl 1860 – 1919   

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German neuropathologist pathology of cortical neurons histological stain for selective visualization of neuronal cell bodies Source Wikipedia

Franz Nissl 

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important work in psychiatry correlating changes in glial cells, blood vessels, and brain tissue with mental illness worked with and was friends with Alois Alzheimer

Dark inclusions are Nissl bodies. Large process is a dendrite.

Membrane potentials 

Nervous and muscle tissue is considered irritable or excitable tissue 

This means that these tissues can respond to a stimulus or change in the environment

Resting and Action potentials 

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Normally the membrane is at rest and when stimulated it responds http:// www.blackwellpublishing.com/matthews/ch

Glial cells 

Oligodendrocytes  

Located in the CNS Produce the myelin sheath

Glial cells  

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Schwann cells Named after Theodor Schwann, German cytologist and physiologist (1810-1882) Father of modern histology

Theodor Schwann   

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Discovered the enzyme pepsin Coined term metabolism Described skeletal muscle in the upper esophagus Discovered myelin sheath on neurons Along with Mathias Schleiden developed cell theory in 1839

Gray Matter

Spinal cord grey matter

Pia Mater

Choroid plexus

Choroid plexus

Choroid plexus

Choroid plexus from book

Cross section of nerve 

Epineurium 

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Perineurium 

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Dense CT and fibroblasts Flattenned, tightjunction epitheliumlike cells

Endoneurium 

Thin reticular CT

Schwann cell nucleus

Axons

Cross section of two small nerves.