This figure depicts the causative factors for constipation. Common physiological factors include:
- overstimulation of the sympathetic system
- inhibition of the parasympathetic system
- significant resorption of water in the large bowel
- lack of significant bulk in the lumen
These physiological effects can arise from co-morbid disease states and/or concomitant drug use (see drug-induced constipation for a listing of drugs that can cause constipation). However, patient-related factors are also common and includ lack of exercise or water intake.
I. Stimulation of sympathetic nerves slows gastrointestinal movements.
II. Increasing parasympathetic tone increases colonic motility.
Extra info: The sympathetic and parasympathetic neurons of the autonomic nervous system have opposite effects on GI motility.