What is the primary function of the nervous system?

The primary function of the nervous system is to send messages to the brain, allowing for communication between different parts of the body and facilitating responses to external stimuli. This system is essential for coordinating bodily functions, controlling movement, and processing sensory information.

When sensory receptors detect stimuli, they send signals through nerve cells to the brain, where the information is processed. The brain then sends out responses, either as voluntary actions (like moving a limb) or involuntary actions (like reflexes). This rapid transmission of signals enables the body to react quickly, ensuring survival and adaptation to changing environments.

The other functions mentioned, such as digesting food, filtering blood, and regulating hormones, are primarily managed by other systems in the body, such as the digestive system, excretory system, and endocrine system, respectively. Each of these systems plays crucial roles but does not fulfill the same communication and response function that the nervous system specializes in.