What effect does the sympathetic nervous system have on GI movement?

The sympathetic nervous system is primarily responsible for the body's "fight or flight" response, which prepares the body for situations requiring increased alertness and energy expenditure. When activated, this system prioritizes blood flow and energy towards the muscles and away from non-essential functions, such as digestion.

As a consequence, sympathetic activation results in a decrease in gastrointestinal (GI) movement. This is achieved through a reduction in the motility of the smooth muscle in the GI tract, which means there is less contraction and movement occurring in this area. Additionally, sympathetic stimulation can inhibit digestive secretions typically associated with the parasympathetic nervous system, further supporting the decrease in overall digestive activity.

In contrast, other systems like the parasympathetic nervous system promote digestion and increase GI movement by enhancing peristalsis and increasing blood flow to the digestive organs. Therefore, the role of the sympathetic nervous system in reducing GI movement aligns with its function of redirecting resources towards more immediate survival needs.