- Pyramidal cell
Infobox_neuron
neuron_name = Pyramidal cell
image_neuron = GolgiStainedPyramidalCell.jpg
caption_neuron = A human neocorticalpyramidal neuron stained via Golgi technique. Notice the apical dendrite extending vertically above the soma and the numerous basal dendrites radiating laterally from the base of the cell body.
location = Cortex esp. Layers III and V
function = excitatory projection neuron
neurotransmitter =Glutamate
morphology = Multipolar Pyramidal
afferents =Superficial cortical layers
efferents = Varies (see text)
GraySubject = 183
GrayPage = 722A pyramidal cell (or pyramidal neuron, or projection neuron) is a multipolar
neuron located in thehippocampus andcerebral cortex . These cells have a triangularly shaped soma, or cell body, a singleapical dendrite extending towards thepial surface, multiplebasal dendrite s, and a singleaxon . Pyramidal neurons compose approximately 80% of the neurons of the cortex, and releaseglutamate as theirneurotransmitter , making them the major excitatory component of the cortex (seesynapse ). The neurons contributing to thepyramidal tract (alias thecorticospinal tract ) are themselves pyramidal neurons, but most pyramidal neurons send axons elsewhere. [ [http://williamcalvin.com/LEM/LEMend.htm] (Reference for this sentence only)]In the
primary motor cortex , layer V pyramidal cells are extremely large. These cells are calledBetz cell s. Their cell bodies can be as large as 100 micrometers in humans. Typical human pyramidal cell bodies range from 10 to 50 micrometers. Also, any pyramidal cell that faces the opposite direction of a Betz cell (i.e. its longest dendrite faces the opposite direction of all of the other Betz cells) is known as aMartinotti cell .Pyramidal cells are tall and conical, triangular in tissue sections. Their apex points toward the brain surface and has a thick dendrite with many branches, and small, knobby dendritic spines. The base gives rise to horizontally oriented dendrites, and an axon that passes into the white matter. Pyramidal cells are the output neurons of the cerebrum. They transmit signals to other parts of the CNS. Their axons have collaterals that synapse with other neurons in the cortex or in deeper regions of the brain.
ee also
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Cerebral cortex
*Pyramidal tract References
External links
* [http://static.howstuffworks.com/gif/brain-neuron-types.gifDiagram]
* [http://neuromedia.neurobio.ucla.edu/campbell/nervous/wp_images%5C198_pyramidal_cells.gifImage]
* [http://www.trinity.edu/rblyston/MicroA/Lectures/L16pt1-html/sld007.htm Diagram (as part of slideshow)]
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