Additional groups of ganglion cells may be found between the inner circular muscle layer and the connective tissue of the submucosa. These groups form the Meissner's plexus. The spiral ganglion is situated inside the modiolus, at the base of the bony spiral lamina, in the cochlea of the inner ear. Observe nerve cell bodies and try to find the satellite cells. Within the ganglion cells, note the large round nucleus with distinct nucleolus and abundant Nissl bodies.
Spiral ganglion is a sensory ganglion.
Remember that these neurons are bipolar and do not have synapses in this ganglion. This thin plastic slide demonstrates nerve cytology particularly well. The round blue structures are myelinated axons. A group of nerve fascicles form the anatomical nerve which is surrounded by dense connective tissue called the epineurium. Under oil immersion it is possible to identify mitochondria which appear as very fine rod-like bodies within the axon.