A motor unit is made up of a motor neuron and the skeletal muscle fibers innervated by that motor neuron's axonal terminals.roups of motor units often work together to coordinate the contractions of a single muscle; all of the motor units within a muscle are considered a motor pool. All muscle fibers in a motor unit are of the same fiber type.
SURFACE STRUCTURE. Basaltic lava flows erupt primarily from shield volcanoes, fissure systems, scoria cones, and spatter cones. These fluid lava flows can be subdivided into two end-member structural types, based primarily on the nature of lava flow surfaces: 1  Pahoehoe Lava -- Surfaces are smooth, billowy, or ropy.
Dark in color, basalt rock is an igneous rock, which are (rocks produced under intense heat. Its dark color is partly as result of the minerals olivine and aspyroxene. Basalt rock forms when hot lava gets to the Earth's surface. This may be either via a mid-ocean ridge or a volcano.