Human feces

Human feces (or human faeces), also known as a stool, is the waste product of the human digestive system including bacteria. It varies significantly in appearance, according to the state of the digestive system, diet and general health.

Normally stool is semisolid, with a mucus coating. Small pieces of harder, less moist feces can sometimes be seen impacted on the distal (leading) end. This is a normal occurrence when a prior bowel movement is incomplete, and feces are returned from the rectum to the intestine, where water is absorbed.

Meconium (sometimes erroneously spelled merconium) is a newborn baby's first feces.

Bristol Stool Chart

The Bristol Stool Chart or Bristol Stool Scale is a medical aid designed to classify the form of human feces into seven categories. Sometimes referred to in the UK as the "Meyers Scale," it was developed by K.W.Heaton at the University of Bristol and was first published in the Scandinavian Journal of Gastroenterology in 1997. The form of the stool depends on the time it spends in the colon.

The seven types of stool are: # Separate hard lumps, like nuts (hard to pass). # Sausage-shaped but lumpy. # Like a sausage but with cracks on its surface. # Like a sausage or snake, smooth and soft. # Soft blobs with clear cut edges (passed easily). # Fluffy pieces with ragged edges, a mushy stool. # Watery stool, entirely liquid.

Types 1 and 2 indicate constipation. Types 3 and 4 are optimal, especially the latter, as these are the easiest to pass Types 5–7 are associated with increasing tendency to diarrhea or urgency. Hematochezia is similarly the passage of feces that are bright red due to the presence of undigested blood, either from lower in the digestive tract, or from a more active source in the upper digestive tract. Alcoholism can also provoke abnormalities in the path of blood throughout the body, including the passing of red-black stool.

Blue

Prussian blue, used in the treatment of radiation, cesium, and thallium poisoning, can turn the feces blue. Substantial consumption of products containing blue food dye, such as blue curaçao or grape soda, can have the same effect.

Silver

A tarnished-silver or aluminum paint-like feces color characteristically results when biliary obstruction of any type (white stool) combines with gastrointestinal bleeding from any source (black stool). It can also suggest a carcinoma of the ampulla of Vater, which will result in gastrointestinal bleeding and biliary obstruction, resulting in silver stool.

Fecal contamination

A quick test for fecal contamination of water sources or soil is a check for the presence of E. coli bacteria performed with the help of MacConkey agar plates or Petri dishes. E. coli bacteria uniquely develop red colonies at temperature of approximately overnight. Although most strains of E. coli are harmless, their presence is indicative of fecal contamination, and hence an increased possibility of the presence of more dangerous organisms.

Fecal contamination of water sources is highly prevalent worldwide, accounting for the majority of unsafe drinking water. In developing countries most sewage is discharged without treatment. Even in developed countries events of sanitary sewer overflow are not uncommon and regularly pollute the Seine River (France) and the River Thames (England), for example.

The main pathogens that are commonly looked for in feces include:

Bacteroides species

Salmonella and Shigella

Yersinia tends to be incubated at , which is cooler than usual Campylobacter incubated at , in a special environment

Aeromonas

Candida if the person is immunosuppressed (e.g., undergoing cancer treatment)

if blood is visible in the stool sample

Cryptosporidium

Entamoeba histolytica

Utilization

Fertilizer

Diarrhea

Many viruses, parasites and bacteria cause diarrhea. Diarrhea occurs when the large intestine fails to reabsorb water to the normal extent. This results in a very liquid stool, increasing the rate of expulsion of the intestinal pathogens.

Fecal markers

The feces can be analyzed for various markers that are indicative of various diseases and conditions. For example, faecal calprotectin levels indicate an inflammatory process such as Crohn's disease, ulcerative colitis and neoplasms (cancer). Also, feces may be analyzed for any fecal occult blood, which is indicative of a gastrointestinal bleeding.

See also

Feces

Composting toilet

Coprophilia

Constipation

Defecation

Diarrhea

Ecological sanitation

Humanure

Meconium

Night soil

Outhouse

Scatology

Shit

References

Category:Gastroenterology Category:Human physiology