In bright light, the pupil constricts to reduce the amount of light entering the eye. In dark or dim light, the pupil dilates to allow more light into the eye to improve vision. Normal pupil size tends to range between 2.0 and 5.0 millimeters, depending on the lighting. The younger you are, the larger your pupils tend to be.
Fecal incontinence is commonly caused by altered bowel habits (generally diarrhea, but also constipation) and conditions that affect the ability of the rectum and anus to hold stool. The sphincter muscles become weaker as you grow older.
Normal bowel control relies on the proper function of the pelvic muscles, the rectum (the lower end of the large intestine), the sphincter muscles (the muscles in the anus), and the nervous system. Injury to any of these areas can result in bowel incontinence. Common causes of bowel incontinence include: Chronic constipation can lead to a fecal impaction. This happens when a stool gets stuck in the rectum.