The Large Intestine

LARGE INTESTINE It is the distal most part of GIT. It acts as a transit for the digested food materials to be extruded out of the body. Two main types of contractions are seen in the large intestine 1. Segmental 2. Peristaltic Functions: 1. They aid in mixing of the contents of colon. 2. Facilitate the absorption by exposing more contents to the mucosa. 3. They propel the contents towards the rectum. Gastrocolic reflex: Upon distension of stomach due to food initiates contractions of the rectum and a desire to defecate, this is called gastrocolic reflex. Functions of large intestine: 1. Absorption of water. Approximately 90% of fluids are reabsorbed in the colon. 2. Reabsorption of Na+, Ca+, Cl-, glucose 3. Secretion of K+ and HCO-3 4. No digestive enzymes are secreted in colon. 5. Mucus secreted by Goblet cells that lubricate the contents. 6. Colonic bacterial flora, E.Coli, Enterobacter areogenes synthesize vitamin K, B-Complex vitamins.

APPLIED: 1. HIRSCSPIRUNG'S DISEASE. Mainly seen in children due to congenital absence of ganglion cells in Myenteric and submucous plexus. This causes the blockage of peristalsis and muscle contractions therefore there is difficulty in passing of the faeces from this segment and faeces accumulate in the intestine. 2. Diarrhea. Increase in frequency of passage of stools is called diarrhea. It may be caused due to infections, typhoid, gastroenteritis, etc.