What is the primary function of sensory (afferent) neurons?

The primary function of sensory (afferent) neurons is to transmit information to the brain and spinal cord. These neurons are responsible for carrying sensory information from various parts of the body, such as the skin, muscles, and internal organs, to the central nervous system (CNS). This process is crucial for the perception of stimuli, allowing the body to respond appropriately to environmental changes.

Sensory neurons pick up signals such as light, sound, touch, temperature, and pain. Once these signals are detected, they are converted into electrical impulses that are relayed along the sensory pathways to the CNS for processing. This capability is fundamental for awareness and interaction with the surroundings, enabling not only perception but also the initiation of appropriate bodily responses.

Other options pertain to different functions of the nervous system; for instance, transmitting information from the CNS to the muscles relates to motor neurons, while activating glandular responses is associated with autonomic functions, and initiating reflex actions involves both sensory and motor neurons working together, but does not accurately capture the primary role of sensory neurons alone.