Compilation of free information about human parts, their function, assembly, repair, and maintenance
Pyramidal cell
| Pyramidal cell | |
|---|---|
 |
|
| Location | Cortex esp. Layers III and V |
| Function | excitatory projection neuron |
| Neurotransmitter | Glutamate |
| Morphology | Multipolar Pyramidal |
| Presynaptic connections | Superficial cortical layers |
| Postsynaptic connections | Varies (see text) |
| Gray's | subject #183 722 |
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.[1]
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.
See also
References
External links
The content of this section is licensed under the GNU Free Documentation License (local copy). It uses material from the Wikipedia article "Pyramidal cell" modified December 22, 2007 with previous authors listed in its history.
