peripheral motor neuron. Etymology: Gk, periphereia + L, motor, mover; Gk, neuron, nerve. an effector neuron located outside the central nervous system, usually in a ganglion of the sympathetic or parasympathetic nervous system.
Gneiss rock is further characterized by its alternating light and dark bands of minerals. Gneiss forms from volcanic rock, shale, or granitic. Quartz is typically abundantly found in gneiss. The bands that form on gneiss rock are due to the various rocks that are a part of its make-up. The use of the word gneiss dates back to the mid-1700s. Gneiss rocks that originate as sedimentary rock are called paragneiss and those originating as igneous rock are called orthogneiss. Limestone can change into calcareous gneiss which contains calcium carbonate.
It means a type of rock texture, not a composition. (more below). Gneiss is a typical rock type formed by regional metamorphism, in which a sedimentary or igneous rock has been deeply buried and subjected to high temperatures and pressures.n gneiss, less than 50 percent of the minerals are aligned in thin, foliated layers. You can see that unlike schist, which is more strongly aligned, gneiss doesn't fracture along the planes of the mineral streaks.