The primary function of sensory neurons in the nervous system is to transmit sensory information from receptors to the central nervous system (CNS). Sensory neurons are responsible for processing external stimuli such as light, sound, touch, and chemical signals, converting them into electrical impulses. These impulses are sent to the brain and spinal cord, where they are interpreted to produce a response, enabling organisms to perceive their environment. This process is essential for survival and interaction with surroundings, allowing organisms to react appropriately to various stimuli, maintain homeostasis, and coordinate movement.