Haustra are small pouches or sacs that form in the colon due to the contraction of the muscle layers in the intestinal wall. These pouches give the colon its segmented appearance. The presence of haustra is a distinguishing feature of the large intestine and is created by the unique structure of the colon, which includes longitudinal muscles that gather the colon into pouches.
The primary function of haustra is to aid in the process of digestion and absorption. As food material moves through the colon, the haustra allow for a more prolonged retention of fecal matter, providing additional time for water and salts to be absorbed back into the body. This function is crucial for forming solid waste before it is eliminated. Moreover, the haustra facilitate the mixing of the contents of the intestine, promoting the breakdown of indigestible substances and supporting the overall digestive process.