The autonomic nervous system and the regulation of body functions

Somatomotor activity and adjustments of the body

All living organisms interact continuously with their environment. They receive multiple signals from the environment via their sensory systems and respond by way of their somatomotor system. Both sensory processing and motor actions are entirely under control of the central nervous system. Within the brain are representations of both extracorporeal space and somatic body domains, the executive motor programs and programs for the diverse patterns of behavior which are initiated from higher levels. The brain generates complex motor commands on the basis of these central representations; these lead to movements of the body in its environment against different internal and external forces. The tools for performing these actions are the effector machines, the skeletal muscles and their controlling somatomotoneurons.

The body's motor activity and behavior are only possible when its internal milieu is controlled to keep the component cells, tissues and organs (including the brain and skeletal muscles) maintained in an optimal environment for their function. This enables the organism to adjust its performance to the varying internal and external demands placed on the organism. In the short term the mechanisms involved include the control of:

• fluid matrix of the body (fluid volume regulation, osmoregulation),

• gas exchange with the environment (regulation of airway resistance and the pulmonary circulation),

• ingestion and digestion of nutrients (regulation of the gastrointestinal tract, control of energy balance),

• transport of gases, nutrients and other substances throughout the body to supply organs, including the brain to maintain consciousness (regulation of blood flow and blood pressure by the cardiovascular regulation),

• […]