The peripheral nervous system comprises the network of nerves and ganglia that extends outward from the central nervous system. Its primary function is to mediate communication between the body's internal processes and the external environment. Sensory receptors throughout the body transmit information regarding stimuli—such as temperature, pressure, or chemical changes—to the central processing areas. Conversely, the system carries motor commands from the brain and spinal cord to the effector organs, allowing for muscle contraction and glandular secretion. These communication pathways are vital for maintaining homeostasis and enabling the coordination of physical movements, defining the body's ability to react dynamically to internal and external changes.