CHAPTER 03 | Digestion, Absorption, and Utilization of Nutrients Figure 3.1 The Digestive System
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Figure 3.1. The Digestive System. Reprinted from National Institute of Diabetes and Digestive and Kidney Diseases, n.d., Retrieved from https://www.niddk.nih.gov/ health-information/digestive-diseases/digestive-system-how-it-works. Reprinted with permission.
enzymes that help digest food (Patricia & Dhamoon, 2022). There is also a layer of smooth muscle in the GI tract that helps food move along and further break down food.
The liver, pancreas, and gallbladder are also involved in the digestive process. The liver produces bile that emulsifies fat and is stored in the gallbladder. The gallbladder stores bile until it is needed in the intestine. Digestive enzymes are mostly produced by the pancreas. These digestive enzymes are sent from the liver and the pancreas to the intestine through small tubes called ducts. Table 3.1 lists the organs and their role in the digestion of food.
As discussed in previous chapters, the body utilizes nutrients. Most foods contain multiple nutrients that need to be broken down into useable parts. This is the process of digestion. For example, body cells cannot use a whole peanut butter and jelly sandwich, but they can use the nutrients from it once the sandwich is digested
The food needs to be broken down into its smallest molecules: amino acids, fatty acids, and either starches or simple sugars, along with the vitamins and minerals that are present. This is necessary to use the nutrients from the food eaten. Essentially, the body takes food apart so that it can use the pieces to rebuild exactly what it needs for life.
Nutrition Fundamentals and Medical Nutrition Therapy