The Nikon MicroscopyU confocal microscopy image gallery was created with a PCM-2000 confocal scanning system interfaced to a Nikon Eclipse E600 upright microscope. Images were recorded in successive z-axis serial sections with C-Imaging Systems software with excitation illumination provided by an argon-ion and/or a helium-neon laser.

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Specialized nerves referred to as motor neurons transmit signals that cause skeletal muscle cells to temporarily shorten or contract. The average mass of the human body is comprised of about forty percent skeletal muscle. Attached to bones and cartilage, these muscle fibers are able to undergo a series of contractions and relaxations that permit movement. Intricate communications between muscles and nerve fibers allow animals to interact with their environment, which includes such daily activities as locomotion or walking.

The bulk of muscle tissue in the body is comprised of striated muscle fibers, which are mostly attached to the skeleton. All muscle fibers are comprised of excitable tissue that can be stimulated mechanically, chemically, or electrically. The two other types of muscle (cardiac and smooth) are comprised of specialized tissues that initiate contractions without requiring stimulation from other sources. Skeletal muscle, however, must receive stimulation from the nervous system in order to contract and is supplied which abundant nervous tissues. Because most skeletal muscle movement is under conscious control, it is also commonly referred to as voluntary muscle.