This document discusses the physiology of acupressure and acupuncture. It begins by describing how acupuncture uses thin needles inserted at specific points along meridian pathways to stimulate the body. Acupressure applies pressure to the same points using tools like rollers or a power mat. The document then explains how sensory stimuli are transduced into electrical signals via sensory receptors and neurons. It describes how graded potentials or action potentials are created and transmitted across chemical synapses and along nerve fibers to initiate impulse transmission through the central nervous system. The key points are intercepted by acupuncture points to create effects.