Large Intestine

Submitted by Thiruvelan on Sat, 11/19/2011
Large Intestine – Digestive System

What is Large Intestine? Large intestine is a tubular organ, which absorbs unabsorbed rare nutrients and water from the digested food for recirculation.

Large Intestine – Digestive System

The large intestine (or large bowel) is the last part of the digestive system; it is about a length of 1.5 meters. It absorbs water from the indigestible food matter from small intestine, and it passes useless wastes from the body. The large intestine needs about 16 hours to complete the remaining digestion processes.

The colon absorbs vitamin K, vitamin B12, thiamine, and riboflavin. It also absorbs sodium, but it eliminates other metallic ions into the wastes. It compact feces and stores fecal matters in the rectum until it is discharges through the anus in defecation.

Caecum and Colon

The large intestine consists of the caecum and colon.

  • Caecum has small projection called the appendix. In human appendix has no known function and considers being a remnant from a previous time in evolution. If the appendix is infected or inflamed, then the condition known as appendicitis is removing by surgery.
  • Colon is inverted 'U' shaped longest part of the large intestine. The colon is classified into 4 sections they are; Ascending colon (goes upward), Transverse colon (goes from right to left), Descending colon (goes downwards) and Sigmoid colon ('S' shaped connection between descending colon and rectum).

Large intestine receives some 10 liters of water per day. 1.5 liters from the food we eat and 8.5 liters by the secretions into the gut. 95% of this water reaches the large intestine is reabsorbing into the body. If water is not reabsorbing, diarrhea can occur that leads to dehydration and ion loss.

When the faeces passed through the colon, it absorbs water, some vitamins, and minerals. The bacteria breakdown fibers into nutrients that is required for the colon to nourish itself. Feces are composed of 75% water and 25% solids. Then the faeces is pushing into the rectum.


The feces stay in the rectum for some time, and it is eliminating by the contraction and relaxation through the anus. The exit of this waste material is control by the anal sphincter.