Definition

The colon is a musculomembranous tube that is the distal part of the gastrointestinal tract and gastrointestinal system.  Partsinclude the cecum, ascending , transverse, descending , sigmoid and rectal portions.  It is connected to the terminal ileum proximally and the anus distally, and  is characterized by its unique function in the production and excretion of feces.

Structural features include  3 longitudinal muscles called taenia coli that run almost the entire length of the colon, sacculations or haustra that result from the “pleating “ of the colon caused by the taenia coli, and odd looking fatty growth excrescences called appendices epiploica that arise from the pericolonic fat.

Functionally, it serves to concentrate fecal effluent by absorbing water and electrolytes, store and control evacuation of fecal material and digest and absorb undigested carbohydrates as a lesser function.

Common diseases include carcinoma, inflammatory diseases, infectious disorders and irritable bowel syndrome.

Clinical evaluation of symptoms such as constipation diarrhea, abdominal colic, and blood in the stool are helpful in diagnosis.  Colonoscopy, biopsy, CTscanning and barium enemas are imaging techniques that help in the diagnostic workup.

Treatment depends on the disease.  Colon cancer usually requires surgical intervention, but radiation therapy and chemotherapy are also used.  Bcterial infections are treated with antimicrobials, and inflammatory diseases with antiinflammatory medications.