Directed from center/directed to center. A centrifugal or efferent nerve fiber transmits impulses from centers in the nervous system to the parts in which the nerves are distributed, thereby exciting muscle contractions or influencing the processes of nutrition, growth, and secretion. A centrifugal force, a form of inertia, tends to move objects away from the center in a system undergoing circular motion (e.g., in throwing the driver of a car against the door when negotiating a sharp bend). A centripetal or afferent nerve fiber or impulse is one originating outside and passing toward the central nervous system. A centripetal force is one whose direction is toward a center. It acts on a body in a curvilinear motion that is directed toward the center of curvature, and which is necessary for a body to move in circular motion (e.g., as in ice skating).
See Axon, Basal ganglia (development), Force, Inertia, Neuron