define

Ganglion refers to a collection of neuron or nerve cell bodies located outside the central nervous system.

 

Synapse is a tiny gap between the ends of nerve fibers across which nerve impulses pass from one neuron to another. At the synapse, an impulse causes the release of a neurotransmitter, which diffuses across the gap and triggers an electrical impulse in the next neuron.

 

Cranial nerves refers to the several nerves that arise in pairs from the brain stem and reach the periphery through openings in the skull. There are 12 such pairs in mammals, birds, and reptiles and usually 10 pairs in amphibians and fish.