What does the automatic nervous system do?
The autonomic nervous system controls and regulates involuntary bodily functions, such as respiration rate, heart rate, and digestion.
The autonomic nervous system can be split into two categories: the parasympathetic and sympathetic nervous systems.
Here is a visual of the parasympathetic nervous system:
The parasympathetic nervous system (also called the rest and digest system) is responsible for relaxing the muscles (e.g. sphincter muscles), slowing down an individual's heart rate, and stimulating digestion and the secretion of saliva.
Let's look at the sympathetic nervous system now:
The sympathetic nervous system sets off the fight or flight response that prepares our body to respond to some sort of danger or vigorous physical activity. It accelerates a few functions such as heart rate, respiration, blood pressure, and glucose production from the liver to the bloodstream so the muscles can have more energy if necessary.