Lecture notes on neural systems, motor systems, movement, actin/myosin, skeletal muscle, steps in a muscle twitch, lower motor neurons, the spinal cord, the motor neuron pool, control of muscle force, reflex behavior, DRG cells, muscle spindles, mono-synaptic reflex arcs, the myotatic reflex, intrafusal fibers, gamma motor neurons, the Golgi tendon organs, the flexor reflex, reciprocal inhibition of flexors and extensors, rhythmic behaviors, central pattern generators, intrinsic oscillators, and mutual inhibition.