Human Body Analytical Essay
The first portion of the digestive track is called the alimentary canal. It is the first part of the complicated process of digesting food. The alimentary canal consists mainly of the esophagus, large intestine, small intestine, oral cavity, pharynx and stomach. Though other organs are also involved in the process such as the tongue, teeth, pancreas, and gallbladder. Peristalsis is the primary rhythmic muscular movement that moves food through the alimentary canal. The teeth are the first means of mechanical digestion. Humans have four types of teeth incisors, canines, bicuspids, and molars.
Chemical digestion starts in the mouth where enzymes like amylase that digests starch begin to break down food. Food travels to the cardiac sphincter that opens and allows the food to pass into the stomach. The stomach contains acid that has a pH of 2. Gastric juices are secreted from gastric pits in the stomach. Mucus cells produce a thick coating called mucus that lines the interior of the stomach and lubricates it as well but most importantly it protects the stomach lining from the strong acids that it produces. Cells called chief cells make a chemical called pepsin. Pepsin breaks down protein. When the food is broken down it enters the duodenum. The duodenum is the first section of the large intestine. Here, most of the chemical digestion that occurs in the body happens. The gallbladder produces a substance called bile that neutralizes acid. The pH in the large intestine becomes a 7 (NEUTRAL). Carbs are digested in the small intestine along with proteins that were not broken down in the stomach. Pancreatic juice aids in the breakdown of macromolecules. Absorption begins in the small intestine. Food continues into the small intestine where food is absorbed and water is regained by the body. Feces is stored in the rectum until it can be released.
For me the best tool for learning this material was to draw out all of the organs and then to label them with color and their names and what they do. I drew a large three page portrait of the digestive system that was correctly labeled and only had two errors that I realized I had made when I was done. I switched the places of the large and small intestine and put the pancreas in the wrong spot. To me all of this knowledge that I acquired in this thematic unit of study shows not how the rest of the world works, but how we work. It is interesting to study because people often separate humans from the rest of the animal kingdom when they really are a part of it.