In anatomy, a ganglion (plural ''ganglia'') is a biological
tissue mass, most commonly a mass of nerve cell bodies. Cells
found in a ganglion are called ganglion cells, though this term
is also sometimes used to refer specifically to retinal ganglion
cells. In neurological contexts, ganglia are composed mainly of
somata and dendritic structures which are bundled or connected
together. Ganglia often interconnect with other ganglia to form
a complex system of ganglia known as a plexus. Ganglia provide
relay points and intermediary connections between different
neurological structures in the body, such as the peripheral and
central nervous systems. There are two major groups of ganglia:
- Dorsal root ganglia (also known as the spinal ganglia) contain
the cell bodies of sensory (afferent) nerves. - Autonomic
ganglia contain the cell bodies of autonomic nerves. In the
autonomic nervous system, fibers from the central nervous system
to the ganglia are known as preganglionic fibers, while those
from the ganglia to t