Pyramidal cell

Pyramidal cell

Infobox_neuron
neuron_name = Pyramidal cell
image_neuron = GolgiStainedPyramidalCell.jpg
caption_neuron = A human neocortical pyramidal 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 = 722

A pyramidal cell (or pyramidal neuron, or projection neuron) is a multipolar neuron located in the hippocampus and cerebral cortex. These cells have a triangularly shaped soma, or cell body, a single apical dendrite extending towards the pial surface, multiple basal dendrites, and a single axon. Pyramidal neurons compose approximately 80% of the neurons of the cortex, and release glutamate as their neurotransmitter, making them the major excitatory component of the cortex (see synapse). The neurons contributing to the pyramidal tract (alias the corticospinal 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 called Betz cells. 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 a Martinotti 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

* 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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