Waste material from the digestive tract that is expelled through the anus. Solidified in the large intestine, faeces are composed of indigestible food residue (dietary fibre), dead bacteria, dead cells from the tract lining, intestinal secretions, bile (which makes faeces brown), and water.
Faeces, or stools, consist of the remainder of the food after it has passed through the alimentary canal and been subjected to the action of the digestive juices, and after the nutritious parts have been absorbed by the intestinal mucous membrane. The stools also contain various other matters, such as pigment derived from the BILE, and large quantities of bacteria which are the main component of human stools. The stools are passed once daily by most people, but infants have several evacuations of the bowels in 24 hours and some adults may defaecate only two or three times weekly. Sudden changes in bowel habit, persistent diarrhoea or a change from the normal dark brown (caused by the bile pigment, stercobilin) to very pale or very dark stools are reasons for seeking medical advice. Blood in the stools may be due to HAEMORRHOIDS or something more serious, and anyone with such symptoms should see a doctor.
Incontinence of the bowels, or inability to retain the stools, is found in certain diseases in which the sphincter muscles – those muscles that naturally keep the bowel closed – relax. It is also a symptom of disease in, or injury to, the SPINAL CORD.
Pain on defaecation is a characteristic symptom of a FISSURE at the ANUS or of in?amed haemorrhoids, and is usually sharp. Pain of a duller character associated with the movements of the bowels may be caused by in?ammation in the other pelvic organs.
CONSTIPATION and DIARRHOEA are considered under separate headings.
n. the waste material that is eliminated through the anus. It is formed in the *colon and consists of a solid or semisolid mass of undigested food remains (chiefly cellulose) mixed with *bile pigments (which are responsible for the colour), bacteria, various secretions (e.g. mucus), and some water. See Appendix 4. —faecal adj.
Faeces that differ from normal in colour, odour, consistency, or content. Abnormal faeces may indicate a disorder of the digestive system or related organ, such as the liver, but a change in the character of faeces is most often due to a change in diet.
Diarrhoea may be due simply to anxiety or may be caused by an intestinal infection (see gastroenteritis); by an intestinal disorder such as ulcerative colitis or Crohn’s disease; or by irritable bowel syndrome. Loose stools may indicate malabsorption. Constipation is generally harmless but, if it develops unexpectedly, may be caused by a large-intestine disorder such as colon cancer.
Pale faeces may be caused by diarrhoea, a lack of bile in the intestine as a result of bile duct obstruction, or a disease that causes malabsorption (such as coeliac disease). Such faeces may be oily, foul-smelling, and difficult to flush away. Dark faeces may result from taking iron tablets. However, if faeces are black, there may be bleeding in the upper digestive tract.
Faeces containing excessive mucus are sometimes associated with constipation or irritable bowel syndrome. Enteritis, dysentery, or a tumour of the intestine (see intestine, tumours of) may result in excess mucus, which is often accompanied by blood.
Blood in the faeces differs in appearance depending on the site of bleeding. Bleeding from the stomach or duodenum is usually passed in the form of black, tarry faeces. Blood from the colon is red and is usually passed at the same time as the faeces. Bleeding from the rectum or anus, which may be due to tumours or to haemorrhoids, is usually bright red. (See also rectal bleeding.)... faeces, abnormal
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