Structure
Granule cells in different brain regions are both functionally and anatomically diverse: the main thing they have in common is smallness. For instance, olfactory bulb granule cells are GABAergic and axonless, while granule cells in the dentate gyrus have glutamatergic projection axons. These two populations of granule cells are also the only major neuronal populations that undergo adult neurogenesis, while cerebellar and cortical granule cells do not. Granule cells have a structure typical of a neuron consisting of dendrites, a soma and an axon.
Dendrites: Each granule cell has 3 – 4 stubby dendrites which end in a claw. Each of the dendrites are only about 15 μm in length.
Soma: Granule cells all have a small soma diameter of approximately 10 μm.
Axon: Each granule cell sends a single axon onto the Purkinje cell dendritic tree. The axon has an extremely narrow diameter: ½ micron.
Synapse: 100-300,000 granule cell axons synapse onto a single Purkinje cell.
The existence of gap junctions between granule cells allows multiple neurons to be coupled to one another allowing multiple cells to act in synchronization and to allow signalling functions necessary for granule cell development to occur.
Read more about this topic: Granule Cell
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