Small Intestine vs Large Intestine
Both small intestine and large intestine are considered as parts of gastro intestinal tract. They have elongated tube like structure with a lumen inside. Intestinal parts are very important as they absorb nutrients and other substances from foods and eliminate waste products from the body.
Small intestine is approximately 4.5m long and is located in between the stomach and large intestine. It helps mainly to digest the foods and absorb the nutrients from the food via the small finger-like projection on its epithelial inner surface called villi. The apical surface of each epithelial cell has cytoplasmic extensions called microvilli. Because of this special structure, the epithelial wall of the small intestine is called a brush border. Villi and microvilli increase the area for absorption and absorption efficiency. Small intestinal can be divided into three parts; duodenum, jejunum, and ileum. The digestion of the food occurs primarily in the duodenum and jejunum.
Large intestine mainly eliminates waste material from our body. It is approximately 1m long, and it forms the last part of the digestive tract. No digestion takes place within the large intestine and only about 4% of absorption of fluids, especially water, occurs there. The inner wall of the large intestine has no villi and has very low absorptive surface area. The functions of the large intestine include the absorption of water and metabolic wastes of bacteria like vitamin K and production of waste material called feces. Many bacteria live and reproduce in this area as it provides undigested food materials as substrates for bacterial fermentation.
What is the difference between Small Intestine and Large Intestine?
• Small intestine is longer than large intestine.
• Generally, width or diameter of the small intestine is smaller than that of the large intestine.
• Almost all parts of the small intestine except duodenum are mobile. In contrast, many parts of the large intestine lack mobility.
• Caliber of filled small intestine is smaller than that of filled large intestine.
• The small intestine has a mesentery that passes downward across the midline into the right iliac fossa unlike the large intestine does.
• The large intestine has fatty tags attached to its wall known as ‘appendices epiploicae’ while the small intestine does not.
• The outer wall of the small intestine is smooth whereas that of the large intestine is sacculated.
• The longitudinal muscle of the small intestine forms a continuous layer around it, while that of the large intestine (except the appendix) is reduced to form three bands called ‘taniae coli’.
• The mucous membrane of the small intestine has villi which are absent in the large intestine.
• The inner wall of the small intestine has permanent folds called plicae circulars, while no such fold is found inside the large intestine wall.
• Payer’s patches (aggregations of lymphoid tissue) are present only in the mucous membrane of the small intestine whereas they are absent in the large intestine.
• The small intestine is located in between the stomach and the large intestine, whereas the large intestine is the last part of gastro-intestinal tract.
• The basic function of the small intestine is to digest foods and absorb nutrients, while that of the large intestine is to re-absorb certain substances from undigested foods and eliminate wastes.