Neuron

A montage of four images of the development of a single neuron over a two-week period. The neuron was transfected with green fluorescent protein and an automated microscope was used to image the neuron 3 h after transfection (pseudocolored blue-green) and then to return to the same neuron periodically and re-image it 64 h (lavender-red), 113 h (orange-purple), and 137 h (purple-gold) later.

Neuron synapse

Comparison of neurons with other cells. Nerve cells have long, invisibly thin fibers that carry electrical impulses throughout the body. Some of these fibers extend about 3 feet—from the spinal cord to the toes! Also shown here, sized proportionately, are a red blood cell, human egg cell, sperm cell, and cone cell of the eye (which allows you to see in color).