Structure and Function of Gastrointestinal Tract

Question: Describe about the Essay for Structure and Function of Gastrointestinal Tract? Answer: The gastrointestinal tract is one of the major organ systems which is responsible for consumption, digestion, absorption of food for nutrition as well as excretion of waste from the body. The system is divided into upper and lower gastrointestinal tracts. It starts from the mouth and ends at the anus (Sherwood 2015). Mouth The first organ of the gastro intestinal tract is the mouth, where the digestion process starts at the time of taking the first bite of food. With the help of teeth and tongue, chewing breaks down food particles into smaller pieces, saliva is mixed with food, making it more feasible for engulfed and absorbed. Esophagus The next part in GI tract is esophagus, the food tract located after mouth and extended to the stomach. It receives food consumed in mouth after swallowing through the series of muscular contractions known as peristalsis and its major function is to bring the food to the stomach (Gropper and Smith 2012). Stomach The next organ in the gastrointestinal tract is stomach, one of the key organs of digestion. It is like a hollow organ containing enzymes for breaking down the received food particles into simpler compounds to be absorbed in small intestine. The cells residing in the lining of the stomach wall secrete digestive enzyme including hydrochloric acid which is responsible for breaking down food. After sufficient processing of food, the digested food is released into the small intestine. Small Intestine In small intestine, the assimilation of food is done. The small intestine is a long muscular tube, consist of three segments known as the duodenum, jejunum and ileum. Here the food received from the stomach is further broken down into smaller components by the use of the enzyme from pancreas and bile salt from the liver. Here the duodenum has a major role in breaking substances in a continuous motion aligning with the peristalsis. In contrast, the jejunum and ileum are responsible for absorbing nutrients from the food into the blood stream. After absorption of the nutrients, the undigested food particles are passed through the small intestine and moves to the colon of the large intestine (Kopf-Bolanz et al. 2012). Large Intestine Large intestine or colon is a 6 feet long muscular tube consisting cecum, rectum and anal canal. The waste food particles left over after absorption in the small intestine; it is passed into the colon, where water is removed and stored into S-shaped in solid form. Bacteria in the large intestine process the waste products by synthesizing vitamins and protecting from harmful bacteria. Then the stool is passed into the rectum. It holds stool, as the chamber becomes full of stool, the process of excretion begins. The last part of the digestive tract is a 2-inch long canal known as the anus, its upper lining can detect rectal contents and it is surrounded by sphincter muscles for controlling stool (Underwood 2012). Accessory organs The accessory includes pancreas, liver and gallbladder and spleen. Pancreas secretes digestive enzymes into the small intestine for breaking down food and insulin in the bloodstream for metabolizing sugar. Liver secretes bile salt into small intestine required for digesting fat. The liver detoxifies harmful chemicals and drugs. The gallbladder is small container storing and concentrating bile and releases into the duodenum. Reference List Gropper, S. and Smith, J., 2012.Advanced nutrition and human metabolism. Cengage Learning. Kopf-Bolanz, K.A., Schwander, F., Gijs, M., Vergres, G., Portmann, R. and Egger, L., 2012. Validation of an in vitro digestive system for studying macronutrient decomposition in humans.The Journal of nutrition,142(2), pp.245-250. Sherwood, L., 2015.Human physiology: from cells to systems. Cengage learning. Underwood, E., 2012.Trace elements in human and animal nutrition 4e. Elsevier.