This electron micrograph shows the synapse between a motor neurone and a muscle cell. Note that there are many mitochondria at the nerve terminal. The synaptic vesicles are visible as small dots. The synaptic cleft is the gap between the motor neurone and the invaginated muscle membrane.
[Electron micrograph kindly provided by Professor Seth Love, Department of Neuropathology, Institute of Clinical Neurosciences, Frenchay Hospital, Bristol]