FUNCTIONS OF THE NERVOUS SYSTEM
The nervous system is involved in some way in nearly every body function. Some major functions of the nervous system are
1. Receiving sensory input. Sensory receptors monitornumerous external and internal stimuli. We are aware of sensations from some stimuli, such as vision, hearing, taste, smell, touch, pain, body position, and temperature. Other stimuli, such as blood pH, blood gases, and blood pressure, are processed at a subconscious level.
2. Integrating information. The brain and spinal cord are themajor organs for processing sensory input and initiating responses. The input may produce an immediate response, be stored as memory, or be ignored.
3. Controlling muscles and glands. Skeletal muscles normallycontract only when stimulated by the nervous system. Thus, by controlling skeletal muscle, the nervous system controls the major movements of the body. The nervous system also participates in controlling cardiac muscle, smooth muscle, and many glands.
4. Maintaining homeostasis. The nervous system plays animportant role in maintaining homeostasis. This function depends on the nervous system’s ability to detect, interpret, and respond to changes in internal and external conditions. In response, the nervous system can stimulate or inhibit the activities of other systems to help maintain a constant internal environment.
5. Establishing and maintaining mental activity. The brain isthe center of mental activity, including consciousness, memory, and thinking.