Digestive System Research Paper

The Digestive System

The digestive system is a system consisting of the mouth, oesophagus, stomach, gallbladder, small intestine, large intestine, the rectum and the anus. The functions of the digestive system are:

• To break down food particles into molecules for digestion

• To absorb into the bloodstream the small molecules produced by digestion

• To eliminate un digested and unabsorbed foodstuffs and other waste products from the body The full digestive process begins at the mouth. The food enters the mouth and is chewed. This is call mastication and it gives the food a greater surface area which enables enzymes to break the food down making it easier to digest. The process of breaking down the food starts with the saliva in your mouth.

The food then travels into the oesophagus. Your oesophagus is located near your trachea (windpipe). The epiglottis separates the nasal cavity and the lower airway from the passage of food whilst swallowing. The contractions of the muscles in your oesophagus push the food down your oesophagus and into your stomach. Your stomach is a hollow organ that holds food whilst it is being broken down by the enzymes. There is also strong acid released by the glands in the lining of the stomach which helps break down food into a more useable form and also aids in the destruction of most ingested bacteria. After the contents have successfully been broken down they are released into the small intestine. The small intestine is a 22 foot long tube that helps to break down the food with enzymes released from the pancreas and bile released form the liver. In this organ the process of Peristalsis is at work, pushing the food further and further through the small intestine towards the colon. These movements are stimulated by the presence of chyme. The small intestine begins with the duodenum which has the large responsibility of continuing to break down the food. The jejunum and ileum are

Slow peristaltic activity moves the stool slowly along the colon. This slow movement allows reabsorption of water and electrolytes. This is the primary purpose of the colon. The large intestine is where the stool is formed. The stool is the leftover waste that has not been absorbed into the cells. The stool begins as a liquid state and slowly forms a solid. The stool is then stored in the sigmoid. The stool is stored here until something called at “mass movement” occurs and empties the stool into the rectum, the mass movement happens about once or twice a day. The stool usually takes about 36 hours to travel through the large intestine. After leaving the large intestine the stool enters the rectum. The rectum is an 8 inch long passage that connects the large intestine and the anus. It is the rectum’s job to store the stool and let the body know that there is a stool that is needed to be let out. When there is gas or stool that is needed to be released the sensors send a message to your brain and the brain decides whether the stool can be released. If the stool can be released the, sphincters relax and the rectum contracts, which then