Imagine you are a chicken sandwich that a person is eating for lunch. Write about your journey through the human body in detail. Where does the journey begin? Where does it end? What do you see along the way? How do you feel? Where is each part of the chicken sandwich digested? Be sure to include the digestive process of each part of the sandwich, including the bread (carbohydrate), chicken (protein), and mayonnaise (fat). Identify the steps or sequentially discuss the organs involved in the digestive system, beginning with the mouth and ending with the anus. Discuss the digestion of each macronutrient and site of absorption. Your answer should be at least three paragraphs long.

When the chicken salad sandwich first enters the mouth the salivary glands produce a digestive juice called salivary amylase which begins to break down or hydrolyse the starch which is in the bread of the chicken salad sandwich. Amylase breaks down carbohydrates, more specifically the starch in the carbohydrates and changes it into maltose; this is a more acceptable form that the body can absorb. As the chicken salad sandwich continues its journey it enters the stomach where it is stored. In the stomach the acid denatures the amylase enzyme which stops it from working. Once the food has moved from the stomach to the small intestine, the pancreatic amylase, which is produced in the pancreatic juices, continues the breakdown of the starch in the bread of the sandwich to a substance called maltose.

As the food is further pushed along the small intestine it produces maltase which breaks down the maltose into an even smaller molecule called glucose. The chicken in the sandwich starts to be broken down in the mouth where it is chewed to make smaller pieces. When it reaches the stomach it begins the hydrolysis process, the stomach produces an enzyme called pepsin, and this partially breaks down the proteins into amino acid. This then travels to the small intestine where the chicken is further broken down by an enzyme called trysin which continues the breakdown of proteins to amino acids. The butter in the chicken salad sandwich is solely broken down in the small intestine into emulsified fats and fatty acids by enzymes produced in the liver and pancreas called bile and lipase.

The lettuce in the chicken salad sandwich cannot be broken down as it is a fibre, so it passes through the system by being chewed into smaller parts and the water is absorbed through the intestinal walls, and ends its journey by leaving the body in the faeces, along with all the other waste products from the chicken sandwich. The end products of the chicken sandwich, sucrose, amino acids, emulsified fats and glycerol/fatty acids are absorbed through the intestinal wall. There is a layer of mucosa that lines the wall that consists of folds which are full of villi which are then covered with microvilli which increases the surface area dramatically. It is through this surface area that the nutrients are absorbed and because of this the amount and rate of absorption is increased.