Histology. Nerve-muscle junction. Colored transmission electron micrograph TEM of a neuromuscular synapse, the junction between a motor neurone axon (nerve fiber) and a muscle fiber. At center (blue) is the end of the nerve, closely associated with a muscle fiber (red, at left). Small vesicles inside the nerve contain neurotransmitter chemicals clustered near to the muscle. A nerve impulse travelling up the nerve causes neurotransmitter chemicals to pass across the gap (synaptic cleft) separating nerve from muscle; the chemicals stimulate or inhibit muscle receptors. A Schwann cell (green) provides the nerve with structural and metabolic support. Magnfication = approx 95,000x at 8x10 inch print size.