Human Digestion

Human Digestion Summary

At the sight and smell of food, the salivary glands in the mouth start the digestive process. Once the food enters the mouth, it is chewed by the teeth and moistened by the saliva. The food is then transformed in to a bolus. The tongue also aids in this process by helping to mix the food and move it between the teeth. Then the food is swallowed and travels in to the pharynx and then into the esophagus. The esophagus is the tube that connects the pharynx to the stomach. Along this region is also the epiglottis which is a valve-like flap of tissue that keeps food from going to the lungs. For example, when it is said “my food went down the wrong pipe”, that wrong pipe is the epiglottis. In the stomach, the bolus is mixed with acid secretions which transform it into chyme. Chyme is described as a semi liquid food mass. The digestion process in the stomach usually takes from two to six hours, depending on the size and type of meal. The liver, gallbladder, and pancreas are organs located close to the stomach that aid in the digestive process. The liver secretes bile which is needed for fat digestion and absorption. The gallbladder stores the bile produced by the liver. The pancreas secretes digestive enzymes and bicarbonate into the small intestine during digestion. From the stomach, the chyme moves into the small intestine. The small intestine is where most of the digestion and absorption of nutrients takes place. The duodenum, the jejunum, and the ileum are the three parts of the stomach. The duodenum continues the digestive process, the jejunum finalizes the process, and the ileum connects the small intestine to the large intestine through the sphincter. The sphincter keeps materials from the large intestine from reentering the small intestine. Once in the large intestine, the unabsorbed material travels through the colon and the rectum to be excreted from the body. The colon and the rectum are parts of the large intestine. Water and...