Glomerulus

Glomerulus /ɡlɒˈmɛrələs/ is a common term used in anatomy to describe globular structures of entwined vessels, fibers, or neurons. Glomerulus is the diminutive of the Latin glomus, meaning "ball of yarn".

Glomerulus may refer to:

See also

Glomerulus (cerebellum)

The cerebellar glomerulus is a small, intertwined mass of nerve fiber terminals in the granular layer of the cerebellar cortex. It consists of post-synaptic granule cell dendrites and pre-synaptic Golgi cell axon terminals surrounding the pre-synaptic terminals of mossy fibers.

Function

The cerebellar glomeruli are the first "processing station" for afferent nerve fibers entering the cerebellum. Input comes from the mossy fibers, which terminate here and synapse with the Golgi and granule cell fibers. The Golgi cells regulate the glomeruli with inhibitory signals, while information is passed on to the granule and Golgi cells from the mossy fiber.

Structure

The structure of the cerebellar glomeruli is about 2.5 um in diameter, and is enwrapped by glial sheathing. Glomeruli are centered on the large axonal terminals of glutamatergic afferent mossy fibers. Each of these terminals come into contact with dendrites from 50–60 different granule cells. The granule cells themselves each have a single or multiple dendrites, and each participate in a different glomerulus. Glomeruli also contain the GABAergic (inhibitory) synapses of Golgi cells onto granule cells, and the glutamatergic (excitatory) synapses from mossy fibers onto Golgi cells. Each glomerulus contains approximately 50 granule cell dendrites, 210 total dendritic digits, and 230 synaptic junctions.